Question

Sergey is solving 5x2 + 20x – 7 = 0. Which steps could he use to solve the quadratic equation by completing the square? Select three options.

Answer 1

Answer:

Step-by-step explanation:

$\mathrm{For\:a\:quadratic\:equation\:of\:the\:form\:}ax^2+bx+c=0\mathrm{\:the\:solutions\:are\:}\\x_{1,\:2}=\frac{-b\pm \sqrt{b^2-4ac}}{2a}\\\mathrm{For\:}\quad a=5,\:b=20,\:c=-7:\quad x_{1,\:2}=\frac{-20\pm \sqrt{20^2-4\cdot \:5\left(-7\right)}}{2\cdot \:5}\\x=\frac{-20+\sqrt{20^2-4\cdot \:5\left(-7\right)}}{2\cdot \:5}:\quad \frac{-10+3\sqrt{15}}{5}\\x=\frac{-20-\sqrt{20^2-4\cdot \:5\left(-7\right)}}{2\cdot \:5}:\quad -\frac{10+3\sqrt{15}}{5}$

$\mathrm{The\:solutions\:to\:the\:quadratic\:equation\:are:}\\x=\frac{-10+3\sqrt{15}}{5},\:x=-\frac{10+3\sqrt{15}}{5}$

Answer 2

Answer:

the answers are b, c, d!

Step-by-step explanation:

just took the test on edge2020 :)