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Would you mind to explain how do you factorize the "red term"?
Kind regards!
This factorization can be performed with a little intuitive testing.
Start with: 15x² - 2x - 1 = 0 Since the last term is -1, we know that the constant terms in the 2 binomials must have a product of -1. So, the first two terms must be +1 and -1. So, we can start with: (__ + 1)(__ - 1) We also know that the first terms in the 2 binomials must have a product of 15x² So, the first two terms must be either 3x and 5x or 15x and x
Let's test 3x and 5x first. We get (3x + 1)(5x - 1) = 0 To see if this factorization is correct, expand and simplify to get: 15x² + 2x - 1 = 0 VERY CLOSE!! We want 15x² - 2x - 1 = 0
So, let's SWITCH the 3x and 5x to get: (5x + 1)(3x - 1) = 0 To see if this factorization is correct, expand and simplify to get: 15x² - 2x - 1 = 0 PERFECT