Question

select the correct answer. find the area of the rectangle below. (3x + 4) feet (x + 3) feet (3x^2 + 13x + 12) square feet (3x^2 + 13x + 7) square feet (3x^2 + 15x + 12) square feet (3x^2 + 10x + 12) square feet

Explanation:

Step1: Recall area formula

$A = l\times w$, where $l = 3x + 4$ and $w=x + 3$.

Step2: Expand product

$(3x + 4)(x + 3)=3x\times x+3x\times3 + 4\times x+4\times3=3x^{2}+9x + 4x+12=3x^{2}+13x + 12$.

Answer:

$(3x^{2}+13x + 12)$ square feet