The formula of an area of a rectangle:
A = wl
We have l = w - 4 and A = 21.
Substitute:
w(w - 4) = 21 <em>use distributive property</em>
(w)(w) + (w)(-4) = 21
w² - 4w = 21 <em>subtract 21 from both sides</em>
w² - 4w - 21 = 0
w² - 7w + 3w - 21 = 0
w(w - 7) + 3(w - 7) = 0
(w - 7)(w + 3) = 0 ↔ w - 7 = 0 ∨ w + 3 = 0
w = 7 ∨ w = -3 < 0
l = w - 4 → l = 7 - 4 = 3
<h3>Answer: the length = 3 u.</h3>
Answer:
72
Step-by-step explanation:
l = 5w
A = l*w
180 = 5w *w
180 = 5w^2
Divide each side by 5
180/5 = 5w^2 /5
36 = w^2
Taking the square root of each side
sqrt(36) = sqrt(w)^2
6 =w
l = 5w = 5*6 = 30
The perimeter is
P = 2(l+w)
P = 2(6+30) = 2(36) = 72
Answer:
b
Step-by-step explanation:
solve for c by simplifying both sides of the equation then isolate the variable
Your answer is 270 hope this helps