Question

Will mark brainliest! Please help!

Answer 1

Answer:

The dimensions are:

$3(2x+1)$ by $(7x+5)$

Step-by-step explanation:

The area of the rectangle is given as

$A=42x^2+51x+15$

The factored form of this quadratic trinomial gives the dimensions of the rectangle.

We factor 3 first to obtain;

$A=3(14x^2+17x+5)$

We split the middle term to get;

$A=3(14x^2+10x+7x+5)$

We factor within the parenthesis to get;

$A=3(2x(7x+5)+1(7x+5))$

We factor further to get;

$A=3(2x+1)(7x+5)$

The dimensions are:

$3(2x+1)$ by $(7x+5)$

Then the perimeter will be

$2(6x+3+7x+5)=26x+16\:\:\:\boxed{\sqrt{} }$