Question

How do you solve `40= 5( x + 9)`?

Answer 1

`x=-1`

Explanation:

equation given
solve `40=5(x+9)`

concept applied
distributive property `a(b+c)=a(b)+a(c)`

calculations
distribute and simplify `40=5(x)+5(9)\rArr40=5x+45`
subtract 45 from both sides `40\color(red)(-45)=5x\cancel(+45)\cancel(\color(red)(-45))`
divide both sides by 5 `(-5)/\color(olive)(5)=(\cancel(5)x)/(\cancel(\color(olive)(5))`

solution
`x=-1`

checking
plug in
`40\stackrel{?}{=}5(-1+9)`
`40\stackrel{?}{=}5(8)`
`40=40`