3x2 + 7x – 13

3x² + 7x - 13 = 0 
36x² + 84x - 156 = 0 
(6x + 7)² - 205 = 0 
(6x + 7)² = 205 
6x + 7 = ±√205 
6x = -7 ± √205 
x = [-7 ± √205] / 6 
x ≈ -3.55 OR x ≈ 1.22

:D?

3 multiplied by 2=6

6-13=-7

7x=-7

x=-1