Answer: The value of x is 5.
To solve this problem, you have to write a proportion to solve for x. The segment on the left and right of the triangle are proportional because the lines are parallel.
So our equation is:
x/(x + 5) = (x - 2)/(x + 1) Cross multiply
x^2 + x = x^2 + 3x - 10 Cancel off the x^2
x = 3x - 10 Subtraction 3x from each side
-2x = -20 Divide by -2
x = 5
