Question

Select one of the factors of 5x2 + 7x + 2.
(5x - 2)
(x + 2)
(5x + 1)
None of the above
I don't want the answer but to know how to solve it. Please and thank you :)

Answer 1

For quadratic equation
\[ax ^{2}+bx+c=0\]
roots are
\[x=\frac{ -b \pm \sqrt{b ^{2}-4ac} }{ 2a }\]

Answer 2

alternatively
\[5x ^{2}+7x+2=0\]
\[5x ^{2}+5x+2x+2=0\]
5x(x+1)+2(x+1)=0
(5x+2)(x+1)=0
so (5x+2) is a root of this equation.

Answer 3

What happened to 7x?

Answer 4

Ohh, ok. I get it. Thank you

Answer 5

you're welcome...:)