Question

What is the value of x ?

Answer 1

21=x

Explanation:

Those angles will add up to 180.

So make your equation 180=3x-3+5x+15

Add like terms, so 3x+5x=8x and -3+15=12

Now you have 180=8x+12

Subtract 12 from both sides, leaving you with 168=8x

Divide by 8 on both sides.

21=x