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625=x^{2}\times 7^{2}
Calculate 25 to the power of 2 and get 625.
625=x^{2}\times 49
Calculate 7 to the power of 2 and get 49.
x^{2}\times 49=625
Swap sides so that all variable terms are on the left hand side.
x^{2}\times 49-625=0
Subtract 625 from both sides.
\left(7x-25\right)\left(7x+25\right)=0
Consider x^{2}\times 49-625. Rewrite x^{2}\times 49-625 as \left(7x\right)^{2}-25^{2}. The difference of squares can be factored using the rule: a^{2}-b^{2}=\left(a-b\right)\left(a+b\right).
x=\frac{25}{7} x=-\frac{25}{7}
To find equation solutions, solve 7x-25=0 and 7x+25=0.
625=x^{2}\times 7^{2}
Calculate 25 to the power of 2 and get 625.
625=x^{2}\times 49
Calculate 7 to the power of 2 and get 49.
x^{2}\times 49=625
Swap sides so that all variable terms are on the left hand side.
x^{2}=\frac{625}{49}
Divide both sides by 49.
x=\frac{25}{7} x=-\frac{25}{7}
Take the square root of both sides of the equation.
625=x^{2}\times 7^{2}
Calculate 25 to the power of 2 and get 625.
625=x^{2}\times 49
Calculate 7 to the power of 2 and get 49.
x^{2}\times 49=625
Swap sides so that all variable terms are on the left hand side.
x^{2}\times 49-625=0
Subtract 625 from both sides.
49x^{2}-625=0
Quadratic equations like this one, with an x^{2} term but no x term, can still be solved using the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}, once they are put in standard form: ax^{2}+bx+c=0.
x=\frac{0±\sqrt{0^{2}-4\times 49\left(-625\right)}}{2\times 49}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 49 for a, 0 for b, and -625 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\times 49\left(-625\right)}}{2\times 49}
Square 0.
x=\frac{0±\sqrt{-196\left(-625\right)}}{2\times 49}
Multiply -4 times 49.
x=\frac{0±\sqrt{122500}}{2\times 49}
Multiply -196 times -625.
x=\frac{0±350}{2\times 49}
Take the square root of 122500.
x=\frac{0±350}{98}
Multiply 2 times 49.
x=\frac{25}{7}
Now solve the equation x=\frac{0±350}{98} when ± is plus. Reduce the fraction \frac{350}{98} to lowest terms by extracting and canceling out 14.
x=-\frac{25}{7}
Now solve the equation x=\frac{0±350}{98} when ± is minus. Reduce the fraction \frac{-350}{98} to lowest terms by extracting and canceling out 14.
x=\frac{25}{7} x=-\frac{25}{7}
The equation is now solved.