8th grade Math Lesson 2-8 Practice

Problems: Show All Work: Solve and graph the solution on a number line.

1.ax - 4 < 12

2.-4(4 + 7x) ≥ -7x + 5

3.2(2x - 8) - 8x ≤ 0

4.5x + (x - 8) > 9/2 (2x - 4)

5.Tom is deciding whether or not he should become a member of the gym to use their basketball courts. The membership cost is $125. Members pay $3 to rent out the basketball courts. How many times can Tom play basketball if he wants to spend no more than $200?

1 answer

1. ax - 4 < 12

To solve for x, we need to isolate the variable on one side of the inequality. Let's start by adding 4 to both sides:

ax - 4 + 4 < 12 + 4

This simplifies to:

ax < 16

Next, divide both sides of the inequality by a:

(ax)/a < 16/a

x < 16/a

The solution is x < 16/a.

To graph this solution on a number line, we will use an open circle to represent the solution and shade the line to the left of the circle to indicate that x is less than the value.

2. -4(4 + 7x) ≥ -7x + 5

Start by simplifying the left side:

-4(4 + 7x) = -16 - 28x

The inequality becomes:

-16 - 28x ≥ -7x + 5

To solve for x, let's first bring all terms with x to one side of the inequality:

-16 - 28x + 7x ≥ 5

Combine like terms:

-16 - 21x ≥ 5

Now, let's isolate x by adding 16 to both sides:

-16 + 16 - 21x ≥ 5 + 16

Simplifying further:

-21x ≥ 21

Divide both sides by -21 (remember to flip the inequality when dividing by a negative number):

x ≤ -1

The solution is x ≤ -1.

To graph this solution on a number line, we will use a closed circle to represent the solution and shade the line to the left of the circle to indicate that x is less than or equal to the value.

3. 2(2x - 8) - 8x ≤ 0

Start by simplifying the left side:

2(2x - 8) - 8x = 4x - 16 - 8x = -4x - 16

The inequality becomes:

-4x - 16 ≤ 0

To solve for x, let's first add 16 to both sides:

-4x - 16 + 16 ≤ 0 + 16

Simplifying further:

-4x ≤ 16

Next, divide both sides by -4 (remember to flip the inequality when dividing by a negative number):

x ≥ -4

The solution is x ≥ -4.

To graph this solution on a number line, we will use a closed circle to represent the solution and shade the line to the right of the circle to indicate that x is greater than or equal to the value.

4. 5x + (x - 8) > (9/2)(2x - 4)

Start by simplifying the left side:

5x + x - 8 > 9x - 18

Combine like terms:

6x - 8 > 9x - 18

To solve for x, let's first subtract 6x and add 18 to both sides:

6x - 8 - 6x + 18 > 9x - 18 - 6x + 18

Simplifying further:

10 > 3x

Now, divide both sides by 3:

10/3 > x

The solution is x < 10/3.

To graph this solution on a number line, we will use an open circle to represent the solution and shade the line to the left of the circle to indicate that x is less than the value.

5. Tom is deciding whether or not he should become a member of the gym to use their basketball courts. The membership cost is $125. Members pay $3 to rent out the basketball courts. How many times can Tom play basketball if he wants to spend no more than $200?

Let's set up an inequality to represent this situation:

125 + 3x ≤ 200

To solve for x, let's first subtract 125 from both sides:

125 - 125 + 3x ≤ 200 - 125

Simplifying further:

3x ≤ 75

Next, divide both sides by 3:

x ≤ 75/3

Simplifying further:

x ≤ 25

Tom can play basketball no more than 25 times if he wants to spend no more than $200.