First, divide 2 out of this expression. y = 2(2x^2 + x - 30)
One way to factor this would be to find the roots using the quadratic formula:
Since a=2, b=1 and c= -15, -1 plus or minus sqrt(1^2-4(2)(-15) x = ------------------------------------------------- 4 -1 plus or minus sqrt(121) -1 plus or minus 11 = -------------------------------------- = ---------------------------- 4 4
One such solution is -12/4, or -3. The corresponding factor is (x+3), and the other is 5/2, leading to the factor (2x-5).
Therefore, </span><span>4x^2 + 2x - 30 = y = 2(2x-5)(x+3).</span>
