Question

Make c the subject: x=-b+(b²-4ac) divided by 2a The brackets mean square root

Answer 1

$x=\dfrac{-b+\sqrt{b^2-4ac}}{2a}\\ 2ax=-b+\sqrt{b^2-4ac}\\ \sqrt{b^2-4ac}=2ax+b\\ b^2-4ac=(2ax+b)^2\\ -4ac=4a^2x^2+4abx+b^2-b^2\\ -4ac=4a^2x^2+4abx\\ c=-ax^2-bx$