Respuesta :

Answer: A=x^2+7x+12

Step-by-step explanation:

A=area of triangle. h=height. b=base

A=bh/2

A=(x+4)(2x+6)/2

A=(x+4)(2x/2+6/2)

A=(x+4)(x+3)

A=x*x+4x+3x+4*3

A=x^2+7x+12