Question

8x² – 22x – 21 = 0

Answer 1

Given: 8x² – 22x – 21 = 0.
On splitting the middle term –22x as 6x – 28x, we get:
8x² + 6x – 28x – 21 = 0
=> 2x(4x + 3) – 7(4x + 3) = 0
=> (4x + 3) (2x – 7) = 0
We know that if the product of two numbers is zero, then at least one of them must be zero.
Thus, 4x + 3 = 0 or 2x – 7 = 0
=> x =$\frac{-3}{4}$ or x = $\frac{7}{2}$
Therefore, the solution of the given equation is x =$\frac{-3}{4}$, $\frac{7}{2}$.