Question

Jill picks a number at random and multiplies it by 2 and adds five to the product. She then multiplies the sum by -3 and subtracts 7 from the product. After these four steps her new number is -40. What was her original number?

Answer 1

Answer:

3

Step-by-step explanation:

Say Jill picks the number x.

She multiplies it by 2 giving 2x.

It says add 5 to that product giving 2x+5.

She multiplies this sum by -3 giving -3(2x+5).

She then subtracts 7 from that product giving -3(2x+5)-7.

Her number after doing all of this is -40 so we hae -3(2x+5)-7=-40

To solve:

First: I would add 7 on both sides:  -3(2x+5)=-33

Second: I would divide boht sides by -3:  2x+5=11

Third: I would subtract 5 on both sides: 2x=6

Last: I would divide both sides by 2:  x=3