Answer is 4 .............
Answer:
x = 7
Step-by-step explanation:

again, we're assuming that both triangles are similar, and thus using proportions.

we do not use the -10, because whatever value "x" may be, can't be negative or even 0.
Factor the equation:
(x-7)(x+4)
Solve for X:
X-7=0 x+4=0
X=7 x=-4
A zero is when the function crosses the x-axis which is solved by setting the function equal to zero.