Question

The perimeter of a rectangle is the same as the

Answer 1

Answer:

a. 20

b. 25

Step-by-step explanation:

Let find the side lengths of the rectangle,

We can complete the square.

${x}^{2} + 4x - 21$

${x}^{2} + 4x = 21$

${x}^{2} + 4x + 4 = 25$

$(x + 2) {}^{2} = 25$

$(x + 2) = 5$

$x = - 7$

or

$(x + 7)$

$x = 3$

or

$(x - 3)$

This means the perimeter of is

2 times -7 equal 14

2 times 3 equal 6

14+6=20.

The side lengths of the square is equal so each side length will measure 5.

${5}^{2} = 25$