Question

The rectangle shown has a length of 4x+3 and a width of 3x. Show your work. (3 points)

Find the perimeter.

Find the area.

Find the perimeter and area if x = 8.

Answer 1

Perimeter 14x + 6 units

Area 12x^2 + 9x

At x = 8

Perimeter is 118 units

Area is 840 square units

Explanation:

The perimeter of the rectangle is 2(l + b)

= 2(4x + 3 + 3x) = 2(7x + 3) = 14x + 6 units

The area of the rectangle is L * B = 3x(4x + 3)

opening the bracket, we have 12x^2 + 9x units

As x = 8

We substitute the value of x in each of the area and perimeter

for perimeter 14x + 6 = 14(8) + 6 = 112 + 6 = 118 units

For the area

12x^2 + 9x = 12(8)^2 + 9(8) = 768 + 72 = 840 square units