Question

Find RT if RS=x+9, ST=1, and RT=2x

Answer 1

2x = x + 9 + 1
(Subtract x on both sides)
x = 9 + 1
(Combined like terms)
x = 10

Answer 2

16 units.

Explanation:

We have that RS = x + 9

RT = 2x and ST = 1

RT + ST = RS

2x + 1 = x + 9

2x - x = 9 - 1 , x = 8

So RT = 2x = 2(8) = 16