How do you solve 3(x-18)=5(x-12)3(x18)=5(x12)?

1 Answer
Mar 25, 2018

x=3x=3

Explanation:

3(x-18)=5(x-12)3(x18)=5(x12)

Let's expand the equation by doing the multiplication
3x-54=5x-603x54=5x60

Now if we add to both sides 5454, this number will be moved from the left to the right
color(red)(+54)+3x-54=5x-60color(red)(+54)+54+3x54=5x60+54

3x=5x-60+543x=5x60+54

Same thing can be applied with 5x5x
color(red)(-5x)+3x=5x-60+54color(red)(-5x)5x+3x=5x60+545x

3x-5x=-60+543x5x=60+54

And what we have to do now is just the sum of the similiar terms
-2x=-62x=6

Multiplying both term by -11, we gain an equation with positive xx
color(blue)(-1)*-2x=-6*color(blue)(-1)12x=61

2x=62x=6

And to finally get the result we can divide both term by 22
2/\color(blue)(2)x=6/color(blue)(2)22x=62

x=3

To check whether the result it's right, just plug in the value in the initial equation. If the left and right quantity are the same we did a good job.