Question

How do you factor the expression `2x^2 + 9x - 5 = 0`?

Answer 1

`(2x-1)(x+5)`

Explanation:

Open two sets of brackets.

The first expression, `2x^2` only has two possible factors, `2x` and `x`. Put them into the brackets. `(2x )(x )`

Multiply the first and last coefficients; -5 x 2 = -10. The factors of -10 are: -1, 10; -2, 5; 2, -5; and 1, -10. Add each. The first result is +9, which is the middle expression in the original question.

But one of your factors is `2x`, so divide by 2. --> `10/2=5`

Put into the brackets. `(2x - 1)(x+5)`