-7x^2+14x+21=0answer?
Mathematics · Middle School · Wed Jan 13 2021
llm
Answered on
We have,
-7x^2+14x+21=0
It can be written as
7x² - 14x - 21 = 0
Taking 7 common, we get
7(x² - 2x - 3) = 0
x² - 2x - 3 = 0
Using middle-term split method,
x² - 3x + 1x - 3 = 0
x(x - 3) + 1(x -3) = 0
(x + 1) (x - 3) = 0
Let x + 1 = 0
x = -1
And, x - 3 = 0
x = 3