Mathematics
19 Online
OpenStudy (haleyelizabeth2017):
Solve the equation.
11 years ago
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (haleyelizabeth2017):
\(x^2+12x+36=25\)
11 years ago
OpenStudy (freckles):
try subtracting 25 on both sides first
so you have something in the form ax^2+bx+c=0
and you could factor ax^2+bx+c or use the quadratic formula to give you x for when ax^2+bx+c=0
11 years ago
OpenStudy (haleyelizabeth2017):
okay :) \(x^2+12x+11\)?
11 years ago
OpenStudy (freckles):
And x^2+12x+11 is actually factorable if you want to factor it
11 years ago
OpenStudy (haleyelizabeth2017):
ummm (x+1)(x+11)? i don't know
11 years ago
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (haleyelizabeth2017):
I think that's it
11 years ago
OpenStudy (freckles):
\[x^2+12x+36=25 \\ x^2+12x+36-25=23-25 \\ x^2+12x+11=0 \\ (x+1)(x+11)=0\]
11 years ago
OpenStudy (haleyelizabeth2017):
okay
11 years ago
OpenStudy (freckles):
yes because 11(1)=11 and 11+1=12
11 years ago
OpenStudy (freckles):
and that second line I hip you notice 23 is suppose to be 25 :p
11 years ago
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (freckles):
hope* lol
11 years ago
OpenStudy (haleyelizabeth2017):
:) yes I did :) what do I do next?
11 years ago
OpenStudy (freckles):
\[x^2+12x+36=25 \\ x^2+12x+36-25=25-25 \\ x^2+12x+11=0 \\ (x+1)(x+11)=0\]
11 years ago
OpenStudy (freckles):
Now since you have a*b=0 then either a=0 or b=0 or both =0
11 years ago
OpenStudy (haleyelizabeth2017):
huh?
11 years ago
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (haleyelizabeth2017):
how do I know that?
11 years ago
OpenStudy (freckles):
so you solve both x+1=0 and solve also x+11=0
\[x^2+12x+36=25 \\ x^2+12x+36-25=25-25 \\ x^2+12x+11=0 \\ (x+1)(x+11)=0 \\x+1=0 \text{ or } x+11=0\]
11 years ago
OpenStudy (freckles):
if a*b=0 then a=0 or b=0 or both =0
because 5*0=0 and 0*2=0 and 0*0=0
11 years ago
OpenStudy (freckles):
at least one of those factors have to be 0
11 years ago
OpenStudy (haleyelizabeth2017):
oh yeah......:)
11 years ago
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (freckles):
so what's your two solutions?
11 years ago
OpenStudy (haleyelizabeth2017):
x=-1 x=-11???
11 years ago
OpenStudy (haleyelizabeth2017):
i have no idea actually
11 years ago
OpenStudy (freckles):
yep x+1=0 when x=-1
and x+11=0 when x=-11
11 years ago
OpenStudy (haleyelizabeth2017):
okay
11 years ago
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (freckles):
You would state the solution as x=-1 or x=-11
11 years ago
OpenStudy (freckles):
or \[x \in \left\{ -1,-11 \right\}\]
11 years ago
OpenStudy (haleyelizabeth2017):
okay....what do I do with that?
11 years ago
OpenStudy (freckles):
Nothing. It is just stating the solution set
11 years ago
OpenStudy (freckles):
It is the set of solutions
11 years ago
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (haleyelizabeth2017):
okay thanks! :)
11 years ago