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:
4
Step-by-step explanation:
<u>24÷(-4</u>)+(-2)·(-5)
-6+<u>(-2)·(-5)</u>
<u>-6+10</u>
4
Answer:
A. Line a and line b
Step-by-step explanation:
Answer:
k = 63
Step-by-step explanation:
3 x 21 = 63
