Question

the sides of triangle x,x + 1, and 2x + 1 its area is xroot10 find x

Answer 1

s, the semi-perimeter = 2.x 
A = √[s.(s-a)(s-b)(s-c)] where a, b and c are the 3 sides. So: 
A = x/√(10) = √[2x(x)(x-1)(1)] = √[2x³-2x²] which, simplified gives: 
x²/10 = 2x³-2x² or 2x = 2.1 giving x= 1.05