Solve for x
x=9
x=-9
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75=x^{2}-6
Multiply both sides of the equation by 3.
x^{2}-6=75
Swap sides so that all variable terms are on the left hand side.
x^{2}-6-75=0
Subtract 75 from both sides.
x^{2}-81=0
Subtract 75 from -6 to get -81.
\left(x-9\right)\left(x+9\right)=0
Consider x^{2}-81. Rewrite x^{2}-81 as x^{2}-9^{2}. The difference of squares can be factored using the rule: a^{2}-b^{2}=\left(a-b\right)\left(a+b\right).
x=9 x=-9
To find equation solutions, solve x-9=0 and x+9=0.
75=x^{2}-6
Multiply both sides of the equation by 3.
x^{2}-6=75
Swap sides so that all variable terms are on the left hand side.
x^{2}=75+6
Add 6 to both sides.
x^{2}=81
Add 75 and 6 to get 81.
x=9 x=-9
Take the square root of both sides of the equation.
75=x^{2}-6
Multiply both sides of the equation by 3.
x^{2}-6=75
Swap sides so that all variable terms are on the left hand side.
x^{2}-6-75=0
Subtract 75 from both sides.
x^{2}-81=0
Subtract 75 from -6 to get -81.
x=\frac{0±\sqrt{0^{2}-4\left(-81\right)}}{2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, 0 for b, and -81 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\left(-81\right)}}{2}
Square 0.
x=\frac{0±\sqrt{324}}{2}
Multiply -4 times -81.
x=\frac{0±18}{2}
Take the square root of 324.
x=9
Now solve the equation x=\frac{0±18}{2} when ± is plus. Divide 18 by 2.
x=-9
Now solve the equation x=\frac{0±18}{2} when ± is minus. Divide -18 by 2.
x=9 x=-9
The equation is now solved.
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Simultaneous equation
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Limits
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