how do you complete the square on this
7x^2 + 10x = -2

Question

amistre64 · Answer

by keeping your wits about you

amistre64 · Answer

factor out the 7 on the left and work out the square part

anonymous · Answer

divide by 7 first?

amistre64 · Answer

$$7x^2+10x=-2$$
$$7(x^2+\frac{10}{7}x)=-2$$
$$7(x^2+\frac{10}{7}x+(\frac{10}{14})^2)=-2+7(\frac{10}{14})^2$$

amistre64 · Answer

then I spose we can get rid of that 7 by dividing both sides :)

amistre64 · Answer

$$x^2+\frac{10}{7}x+(\frac{10}{14})^2=-\frac{2}{7}+(\frac{10}{14})^2$$
compact the left
$$(x+\frac{10}{14})^2=-\frac{2}{7}+(\frac{10}{14})^2$$
and work the rest thru

amistre64 · Answer

yes, divide off the 7 first :)

anonymous · Answer

i can get to the point where i get (x = (10/14))^2 = 44/196 but dont know what to do after this

amistre64 · Answer

you sqrt the sides to unto the ^2 and add off the 10/14

anonymous · Answer

is the answer (-5+ Sqrt11)-14

amistre64 · Answer

$$\sqrt{(x+\frac{10}{14})^2=-\frac{2}{7}+(\frac{10}{14})^2}$$
$$x+\frac{10}{14}=\pm\sqrt{-\frac{2}{7}+(\frac{10}{14})^2}$$
$$x=-\frac{10}{14}\pm\sqrt{-\frac{2}{7}+(\frac{10}{14})^2}$$

anonymous · Answer

i mean (-5 + sqrt11)/14

amistre64 · Answer

the sqrt has 2 parts to it a + and a - that has to be accounted for

amistre64 · Answer

x^2 = 4

x = sqrt(4)

x = 2, or -2

amistre64 · Answer

heres a simple dbl chk http://www.wolframalpha.com/input/?i=7x%5E2+%2B+10x+%3D+-2

amistre64 · Answer

looks to be a /7 not /14

anonymous · Answer

ok thanks a mill

amistre64 · Answer

yep