I don't know how to find the value of x in the isosceles triangle.

x=4

Step-by-step explanation:

split the triangle into two and you will get another smaller triangle as shown in what I have drawn

so notice that there's a right angle?? this means that this is a right angle triangle and you can use Pythagoras theorem to solve it

so by Pythagoras theorem, 5^2= 3^2 + x^2

then you can solve for x

answer:   (s+1)(s+4)

step-by-step explanation:

factor s2+5s+4

s2+5s+4

=(s+1)(s+4)