(x+4)(2x-3)=6
what is the answer ?
(x + 4)(2x - 3) = 6
2x^2 + 8x - 3x - 12 = 6
2x^2 + 5x - 12 - 6 = 6 - 6
2x^2 + 5x - 18 = 0
Use the quadratic formula to find the roots.
-b ± √(b^2 - 4ac)
x = ---------------------------
2a
-5 ± √(5^2 - 4(2)(-18))
x = -----------------------------
2(2)
-5 ± √(25 - (-144))
x = -----------------------------
4
-5 ± √(169)
x = ----------------
4
-5 ± 13
x = -----------
4
-5 + 13 -5 - 13
x = ----------- and x = -----------
4 4
8 -18
x = --- and x = ------
4 4
x = 2 and x = -4.5