Question

What are the answers and work for 15, 18, and 21

Answer 1

15) Here is the equation:

`(a)/(5) - 2 = 9`

Add 2 to both sides and it becomes:

`(a)/(5) = 11`

Switch that around and it becomes:

`11 * 5 = a`

The sign changes. First you were dividing and now you're multiplying.

`11 * 5 = 55`

a = 55

18) Here is the equation:

`(2)/(3) g + 6 = -12`

Subtract 6 and it becomes:

`(2)/(3) g = -18`

Divide by
`(2)/(3)` to leave the variable alone

`(2)/(3) g / (2)/(3) = -18 / (2)/(3) \\ -18 / (2)/(3) = -18 * (3)/(2) = -(54)/(2) = -27`

g = -27

21) Here is the equation:

`(c-5)/(4) = 3`

First multiply both sides by 4 to get rid of the denominator for c

`4 * 3 = 12`

The remaining is -5. Switch it and it becomes +5. Add 5.

`12 + 5 = 17`

c = 17

Answer 2

To solve equations such as the ones you listed above, our end goal is to isolate the variable (the letter that represents an unknown value).

Let’s begin with Number 15.

a/5 - 2 = 9

Due to the reverse order of operations, we should first add 2 to both sides of the equation.

a/5 = 11

To solve, we should multiply both sides by 5 to get rid of the denominator on the variable a.

a = 55 (answer)

Next, we can move onto number 18.

2/3g + 6 = -12

To solve this equation, we should begin by subtracting 6 from both sides.

2/3g = -18

Next, we can get the variable g alone by multiplying both sides by 3/2 (this will cancel out the coefficient of 2/3 on the variable g).

g = -27 (answer)

Finally, we can solve number 21 in a similar manner.

(c-5)/4 = 3

To solve this problem, we should first multiply both sides by 4 to get rid of the denominator on the variable c.

c - 5 = 12

To finish our simplification, we should add 5 to both sides of the equation to get the variable c completely alone.

c = 17 (answer)

Therefore, your answers to questions 15, 18, and 21, are 55, -27, and 17, respectively.

Hope this helps!