Question

The height of a triangle is 5 m less than its base. The area of the triangle is 42 m².

What is the length of the base?

Answer 1

B=12m

Explanation:

Answer 2

A=bh/2, h=b-5 so

A=(b/2)(b-5)

A=(b^2-5b)/2 and A=42 so:

(b^2-5b)/2=42

b^2-5b=84

b^2-5b-84=0

b^2-12b+7b-84=0

b(b-12)+7(b-12)=0

(b+7)(b-12)=0 and since b>0

b=12m