Solving Nonlinear Inequalities, Finding Function Domains, and Graphing

Published on March 1, 2026

Functions

This document covers solving various nonlinear inequalities (quadratic, rational, absolute value), determining the domains of complex algebraic and radical functions, and sketching graphs of piecewise and standard functions.

Question

solve these questions with proper steps

Answer

This appears to be a set of mathematics problems from a Pre-Calculus assignment. I will solve the problems visible in the provided images, addressing Question 1 (Inequalities), Question 2 (Domains), Question 3 (Graphing), Question 4 (Piecewise Graphs), and Question 5 (Function Definition).

Question 1: Solve the nonlinear inequality. Express the solution using interval notation and graph the solution set.

i.

Step 1: Rewrite the inequality to have 0 on one side.
Step 2: Find the roots of the corresponding quadratic equation .
We can factor the quadratic:
The roots (critical points) are and .
Step 3: Test intervals.
The critical points divide the number line into three intervals: , , and . Since the parabola opens upwards (because the leading coefficient ), the expression will be positive outside the roots and negative between the roots. We are looking for where .
  • Test : (True)
  • Test : (False)
  • Test : (True)
Step 4: Write the solution in interval notation.
Since the inequality is , the endpoints are included.
Solution:
Graph: A number line with closed circles at and , shading extending to the left from and to the right from .

ii.

Step 1: Rewrite the inequality.
Multiply by and reverse the inequality sign:
Step 2: Analyze the expression.
Since for all real , then .
Therefore, .
Since , the inequality is always true for all real numbers .
Step 3: Write the solution in interval notation.
Solution:
Graph: A number line entirely shaded, with arrows on both ends.

iii.

Step 1: Rewrite the inequality to have 0 on one side.
Step 2: Combine terms using a common denominator.
Step 3: Analyze the resulting inequality.
For the fraction to be positive, the numerator and denominator must have the same sign.
The numerator is , which is always negative.
Therefore, the denominator must also be negative for the overall fraction to be positive:
Note: The critical points are where the numerator is zero (none) or the denominator is zero ( ).
Step 4: Write the solution in interval notation.
Solution:
Graph: A number line with an open circle at , shading extending to the left.

iv.

Step 1: Rewrite the inequality to have 0 on one side.
Step 2: Combine terms using a common denominator.
Step 3: Find the critical points.
The expression changes sign when the numerator or denominator is zero:
Numerator: ; .
Denominator: .
Critical points: .
Step 4: Test intervals.
Intervals: , , , . We seek where the expression is negative .
  • Test : (False)
  • Test : (True)
  • Test : (False)
  • Test : (True)
Step 5: Write the solution in interval notation.
Since the inequality is strict ( ), the endpoints are excluded.
Solution:
Graph: A number line with open circles at , shading in the region between and , and the region to the right of .

v.

Step 1: Solve the absolute value inequality.
The inequality is equivalent to .
Step 2: Isolate .
Subtract 5 from all parts of the inequality:
Step 3: Write the solution in interval notation.
Solution:
Graph: A number line with open circles at and , shading the region between them.

vi.

This is a compound inequality.
Step 1: Isolate in the middle.
Subtract 7 from all parts:
Step 2: Divide all parts by 3:
Step 3: Write the solution in interval notation.
Since the inequality includes , the endpoints are included.
Solution:
Graph: A number line with closed circles at and , shading the segment between them.

vii.

Step 1: Isolate the absolute value expression.
Step 2: Analyze the result.
Since the absolute value must be non-negative (i.e., ), multiplying by 7 gives .
Since , the statement is true for all real numbers .
Step 3: Write the solution in interval notation.
Solution:
Graph: A number line entirely shaded.

viii.

Step 1: Rewrite the inequality to have 0 on one side.
Step 2: Combine terms using a common denominator.
Multiply by and reverse the inequality sign:
Step 3: Find the critical points.
Numerator roots: and .
Denominator root: .
Critical points: .
Step 4: Test intervals.
Intervals: , , , . We seek where the expression is negative ( ).
  • Test : (True)
  • Test : (Note: )
    (False)
  • Test : (Note: )
    (True)
  • Test : (False)
Step 5: Write the solution in interval notation.
Since the inequality is strict ( ), the endpoints are excluded.
Solution:
Graph: A number line with open circles at , , and , shading the region between and , and the region between and .

Question 2: Find the Domains of following functions.

The domain of a function is the set of all possible input values ( ) for which the function is defined. Restrictions usually arise from:
  1. Division by zero.
  2. Taking the square root (or even root) of a negative number.

i.

Division by zero is the only restriction. Set the denominator to zero:
The function is undefined at .
Domain: or .

ii.

There are two restrictions:
  1. The numerator requires (for the square root).
  2. The denominator cannot be zero: .
Find the roots of the denominator:
Roots are and .
We must satisfy AND AND .
Since , the condition is automatically satisfied.
We must exclude from the set .
Domain: or .

iii.

Set the denominator to zero:
or .
The function is undefined at and .
Domain: or .

iv.

The expression under the square root must be non-negative:
From problem 2(ii), we know the roots are and .
Since the parabola opens upwards, the expression is outside the roots.
Domain: or .

Question 3: Sketch the graph of the function by first making a table of values.

i.

Domain: Requires , so . Domain is .
Point
Sketch: The graph starts at the origin and extends to the left and up, resembling the square root function reflected across the y-axis.

ii.

We consider cases based on the definition of :
Case 1: If , . .
Case 2: If , . .
Point
(Boundary)
Sketch: For , the graph is the line (the x-axis). At , the value is 0. For , the graph is the line . The graph is a single ray along the x-axis for , meeting the line at the origin.

iii.

This is the standard cubic function shifted down 8 units.
Point
Sketch: A smooth, increasing curve passing through and .

Question 4: Sketch the graph of the piecewise defined function.

i.

Piece 1: for (Open circle at )
At : . Boundary point is (open).
Test : . Point .
Piece 2: for (Closed circle at )
At : . Boundary point is (closed).
Test : . Point .
Test : . Point .
Sketch: A ray with slope 2 ending at an open circle at . A ray starting from a closed circle at with slope . There is a jump discontinuity at .

ii.

Note: Assuming simplifies to for .
Piece 1: for (Closed circle at )
At : . Boundary point is (closed).
Test : . Point .
Test : . Point .
Piece 2: for (Open circle at )
At : Limit approaches 1. Boundary point is (open).
For , the graph is the horizontal line .
Sketch: A segment of a downward-opening parabola ( ) that includes the point . At , the function jumps up to an open circle at and continues horizontally as for all .

Question 5: Determine whether the equation defines as a function of .

For to be a function of , every input must correspond to exactly one output . This often means solving for and checking if we get one or two results.

i.

Solve for :
For any given , yields a single non-negative value, so yields a single non-positive value.
Result: Yes, this defines as a function of .

ii.

This is the equation of a circle centered at with radius .
Solve for :
For any such that (i.e., ), there will be two corresponding values (one using and one using ).
Result: No, this does not define as a function of (it fails the vertical line test).

iii.

Solve for :
This equation requires . For any positive , there are two real values of (one positive, one negative). For example, if , .
Result: No, this does not define as a function of .