Answer:
x = - 4 , x = - 3
Step-by-step explanation:
- 7x = x^2 + 12
Take all terms to one side of equation.
x^2 + 7x + 12 = 0
Find which 2 numbers multiply to give 12 and add to give 7.
a × b = 12
a + b = 7
a = 4
b = 3
Split the middle term using these 2 numbers.
x^2 + 4x + 3x + 12 = 0
Factorise each pair of terms separately.
x ( x + 4 ) + 3 ( x + 4 ) = 0
Bring out common factor of ( x + 4 ) and factorise.
( x + 4 ) ( x + 3 ) = 0
Using the Null factor law, make the expressions in each pair of parentheses equal 0.
x + 4 = 0
x = - 4
AND
x + 3 = 0
x = - 3
THEREFORE:
x = - 4 , x = - 3
