The area of the triangle is 56 m2. Find the length of the base.

you need to know the formula to find out area first.

Area = (1/2) * base*height

So, when you let base as x m then, definitely height becomes (x+6) m.

So substitute the values in above formula and you'll get the answer.

I think 56=1/2 (x) (x+6)