V2+4v-21=0 (solve by factoring)

(v + 7)(v -3)

Step-by-step explanation:

(v +7)(v -3)

v x v = v^2

v x -3 = -3v

7 x v = 7v

7 x -3 = -21

v^2 -3v +7v -21 = v^2 +4v -21 = 0

The answer is (v - 3)(v + 7).

Step-by-step explanation:

First, you have to elaborate it :

v² + 4v - 21 = 0

v² - 3v + 7v - 21 = 0

Next, you have to collect like terms :

v(v - 3) + 7(v - 3) = 0

(v - 3)(v + 7) = 0