The Student Room Group
Hanz_a93
5-3x=20

I know that the value of x=-5 but how do i show the working out??!?!?:confused: :confused:


5 - 3x = 20

- 3x = 15

x = -5

Simples.
Reply 2
5-3x=20
5-20-3x=0
-15-3x=0
-15=3x
x=-5
Reply 3
Hanz_a93
5-3x=20

I know that the value of x=-5 but how do i show the working out??!?!?:confused: :confused:


add 3x to both sides of the =
5 - 3x + 3x = 20 + 3x
5 = 20 + 3x

take 20 away from both sides of =
5 - 20 = 20 + 3x - 20
-15 = 3x

divide both sides by 3

-5 = x
x = -5


i.e. loads of different ways that are basically doing the same thing mathematically to both sides of the equation until you get x's on one side and a number on the other