Ask
your own question, for FREE!
Mathematics
8 Online
OpenStudy (anonymous):
quadratic equation
2x^2 - 8x = -7.
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (amistre64):
yes it is
OpenStudy (anonymous):
...
OpenStudy (amistre64):
it is a quad eq; what are you spose to do with it?
OpenStudy (anonymous):
i can't figure this one out
OpenStudy (amistre64):
me either ...
what is it that we are trying to figure out?
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (anonymous):
the answer is going to be
-2 \[\pm\] sqrt 2
-2 \[\pm\] 2 sqrt 2
-2 \[\pm\] sqrt 2
----------------
2
-2 \[\pm\] sqrt 2/2
OpenStudy (anonymous):
that came out bad
OpenStudy (amistre64):
oh, you want to know the x intercepts
OpenStudy (anonymous):
yes
OpenStudy (amistre64):
using what method? complete square, quad formula, or other?
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (anonymous):
quadratic formula
ax^2 + bx+ c = 0
then
-b +or- sqrt b^2 -4ac
-------------------
2a
OpenStudy (amistre64):
complete the square
2x^2 - 8x = -7
2(x^2 - 4x) = -7
2(x^2 -4x +4 - 4) = -7
2(x^2 -4x +4) - 2(4) = -7
2(x -2)^2 - 8 = -7
2(x -2)^2 = -7 + 8
(x -2)^2 = 1/2
x-2 = +- sqrt(1/2)
x =2 +- sqrt(1/2)
OpenStudy (amistre64):
\[ax^2 + bx + c=0\]
\[x=\frac{1}{2a}(-b\pm\sqrt{b^2-4ac})\]
OpenStudy (amistre64):
2x^2 -8x +7 = 0
\[x=\frac{1}{2.2}(--8\pm\sqrt{(-8)^2-4.2.7})\]
\[x=\frac{1}{4}(8\pm\sqrt{64-56})\]
\[x=\frac{1}{4}(8\pm\sqrt{8})\]
\[x=\frac{1}{4}(8\pm\sqrt{4.2})\]
\[x=\frac{1}{4}(8\pm\sqrt{4}\ \sqrt{2})\]
\[x=\frac{1}{4}(8\pm2\sqrt{2})\]
OpenStudy (anonymous):
thanks
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (amistre64):
yep
Can't find your answer?
Make a FREE account and ask your own questions, OR help others and earn volunteer hours!
Join our real-time social learning platform and learn together with your friends!