Question

This is really confusing I could really use some help with this thank you.

Answer 1

15) 2x-5=-20

2x-5+5=-20+5

2x=-15

`(2x)/(2)=(-15)/(2)`

`x=-(15)/(2)`

16) x/3-7=11

x/3=11+7

x/3=18

x=18*3

x=54

17)
`(9x)/(4)=-9`

`(4\cdot \:9x)/(4)=4\left(-9\right)`

`9x=-36`

`(9x)/(9)=(-36)/(9)`

`x=-4`