How do you factor -x ^ { 2} + 10x + 7?
2 Answers
Jul 5, 2018
Explanation:
This does not factor with integer coefficients: consider the quadratic determinant,
Solve the expression equal to zero to find the non-integer coefficients:
Quadratic formula:
So
Jul 5, 2018
Explanation:
"using the method of "color(blue)"completing the square"
=-(x^2-10x-7)
=-(x^2+2(-5)x color(red)(+25)color(red)(-25)-7)
=-(x-5)^2+32
=32-(x-5)^2
"factor using "color(blue)"difference of squares"
•color(white)(x)a^2-b^2=(a-b)(a+b)
"with "a=4sqrt2" and "b=x-5
=(4sqrt2-(x-5))(4sqrt2+x-5)
=(4sqrt2-x+5)(4sqrt2+x-5)