Answer:

Explanation:
We have been given with the quadratic equation 
We have general formula to find the roots of a quadratic equation first we find the discriminant with formula

and after that to find the variable suppose x we have the formula

And general quadratic equation is

On comparing the given quadratic equation with genral quadratic equation we will have values
a=1, b=-7 and c=-6
After substituting these values in the formula we will get

After substituting in the formula to find x we will get

Answer: When the quadratic equation can be factored or solved by completing the square, you do not need to use the quadratic formula
Step-by-step explanation: In the form ax² + bx + c
Whenever <em><u>a</u></em> is 1 (implied, no coefficient of x²) and the constant, <u><em>c</em></u>, is a multiple of numbers whose sum or difference is equal to <u><em>b</em></u>, factoring is much quicker and easier than using the quadratic formula.
Even when there is a coefficient of x², there are procedures to find the factors and solve for x without resorting to the quadratic formula.