To complete the square make sure all the variable terms are on one side of the equation. Then, divide both sides of the equation by a so the coefficient of x^2 is 1.
x_1=1, x_2=- 7
Practice makes perfect
We want to solve the quadratic equation by completing the square.To do so, we will start by rewriting the equation so all terms with x are on one side of the equation.
2x^2+12x+20=34 ⇔ 2x^2+12x=14
Now let's divide each side by 2 so the coefficient of x^2 will be 1.
2x^2+12x=14
⇓
x^2+6x=7
In a quadratic expression b is the linear coefficient. For the equation above, we have that b=6. Let's now calculate ( b2 )^2.
