Answers

2016-07-20T20:31:22+08:00
2x^2-72=0
2x^2-72=0 divide the both side by the value of a.
x^2-36=0
x^2=36
then get the square root.
x=6 -answer

3t^2-12t-63=0
t^2-6t-21=0
t^2-6t+9=21+9
1/2 (-6)=(-3)^2=9
t^2-6t+9=30
(t-3)^2=30
t-3=+-30
t=30+3 | t=-30+3
t=33 and t=-27 -answer
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