Answer :
3x^2 - 16x - 7 = 5. This is a quadratic equation. Cross the 5 to the other side.
3x^2 - 16x - 7 - 5 = 0
3x^2 - 16x - 12 = 0. Let us use factorization method.
Multiply the first coefficient and last term = 3 * -12 = -36.
We think of two numbers that multiply to give -36 and add up to give the middle coefficient -16.
The two numbers are = 2 and -18.
2 * -18 = -36.
2 + (-18) = -16.
We replace the middle term -16 with 2 +(-18) = 2 - 18.
3x^2 - 16x - 12 = 0
3x^2 + 2x - 18x - 12 = 0 Factorize.
x(3x + 2) - 6(3x + 2) = 0
(3x + 2) (x -6) = 0.
Therefore (3x + 2) = 0 or (x -6) = 0
(3x + 2) = 0 x - 6 = 0
3x = 0 -2 x = 0 + 6
3x = -2 x = 6
x = -2/3
3x = -2
x = -2/3
Therefore x = -2/3 or 6.
3x^2 - 16x - 7 - 5 = 0
3x^2 - 16x - 12 = 0. Let us use factorization method.
Multiply the first coefficient and last term = 3 * -12 = -36.
We think of two numbers that multiply to give -36 and add up to give the middle coefficient -16.
The two numbers are = 2 and -18.
2 * -18 = -36.
2 + (-18) = -16.
We replace the middle term -16 with 2 +(-18) = 2 - 18.
3x^2 - 16x - 12 = 0
3x^2 + 2x - 18x - 12 = 0 Factorize.
x(3x + 2) - 6(3x + 2) = 0
(3x + 2) (x -6) = 0.
Therefore (3x + 2) = 0 or (x -6) = 0
(3x + 2) = 0 x - 6 = 0
3x = 0 -2 x = 0 + 6
3x = -2 x = 6
x = -2/3
3x = -2
x = -2/3
Therefore x = -2/3 or 6.
