Question

Use the quadratic formula to solve x2 + 8x = –2

Answer 1

\[x = \frac{ -b \pm \sqrt{b^2 - 4ac} }{ 2a }\]

Answer 2

\[x^2 + 8x = –2\]
--add +2 to both sides.
\[x^2 + 8x + 2 = 0\]

now use the quadratic formula.

Answer 3

x2+8x=-2
+2 +2
x2+8x+2=0 a=1 b=4 c=2

Answer 4

where:
a = 1
b = 8
c = 2

plug them into the formula.

Answer 5

do the 8 turn positive

Answer 6

the 8 stays positive.

Answer 7

but b = 8 not 4... you put b = 4?

Answer 8

I got 8+/- {8}/2

Answer 9

wait that's wrong

Answer 10

im stuck

Answer 11

what are you stuck on? Any step in particular?

Answer 12

yes it the step after I got 8+/-(64-8
____________
2

8+/-(56
_________
2

Answer 13

\[x = \frac{ -(8) \pm \sqrt{(8)^2 - 4(1)(2)} }{ 2(1) }\]
\[x = \frac{ -8 \pm \sqrt{64 - 8} }{ 2 }\]
\[x = \frac{ -8 \pm \sqrt{56} }{ 2 }\]
\[x = \frac{ -8 \pm 2 \sqrt{14} }{ 2 }\]
Can you simplify from here? Any questions just ask away :D

Answer 14

i may have to watch a video on youtube....quadratic's are one of my weak topic's

Answer 15

@some_someone how'd you get to the 14? and do the -8 turn into a positive 8?

Answer 16

\[\sqrt{56} = 2\sqrt{14}\]