Question

Solve x2 + 10x = -21.

x = 7 and x = 3

x = -7 and x = -3

x = -7 and x = 3

x = 7 and x = -3

Answer 1

First we need to put the -21 on the other side of the equal sign. So the equation reads\[x^2+10x+21\]

Answer 2

Do you want to do the quadratic formula or factoring

Answer 3

I'm not sure. Whatever one will work.

Answer 4

Both will work, I'll do it both ways i guess.
\[x=\frac{ -b \pm \sqrt{b^2-4ac} }{ 2a }\]
a=1
b=10
c=21
\[\frac{ -10 \pm \sqrt{10^2-4(1)(21)} }{ 2(1) }\]
\[\frac{ -10\pm \sqrt{100-84} }{ 2 }\]
\[\frac{ -10 \pm \sqrt{16}}{ 2 }\]
This will break into 2 equations
\[\frac{ -10 + 4 }{ 2 }\]
and
\[\frac{ -10-4 }{ 2 }\]

Answer 5

Can you solve the last 2 for me plz?

Answer 6

-3 and -3 ?

Answer 7

you got the first one right not the second one tho
(a negative minus a number will decrease the number)
\[\frac{ -14 }{ 2 }\]

Answer 8

-7? @KlOwNlOvE

Answer 9

sorry was afk, yes the solution set would be -7 -3