How would you solve this squared equation?

Question

(3x+1)²-5(4x-1)

Answer 1

Ah, yes, simplifying (not solving. As pointed out, you solve an equation, but you are simplifying an expression). This can get confusing. The beginner would square 3x + 1 and get 9x² + 1, buuuuuut what you have to remember is that (3x + 1)² = (3x + 1)(3x + 1)

 

(3x + 1)²  - 5(4x - 1)

(3x + 1)(3x + 1) - 5(4x - 1)

3x(3x) + 1(3x) + 3x(1) + 1(1) - 5(4x) - 5(-1)

9x² + 3x + 3x + 1 - 20x + 5

9x² - 14x + 6

 

 

Answer 2

9x^2 + 6x +  1 - 20x + 5 =

 

9x^2 - 14x + 6