Question 136640
X^2+(X+5)^2=25^2
X^2+X^2+10X+25=625
2X^2+10X+25-625=0
2X^2+10X-600=0
2(X^2+5X-300)=0
2(X+20)(X-15)=0
X-15=0
X=15 ANSWER.
PROOF:
15^2+20^2=25^2
225+400=625
625=625