( 19,2 ) ^ { 2 } + b ^ { 2 } = 24 ^ { 2 }
Solve for b
b=14,4
b=-14,4
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368,64+b^{2}=24^{2}
Calculate 19,2 to the power of 2 and get 368,64.
368,64+b^{2}=576
Calculate 24 to the power of 2 and get 576.
368,64+b^{2}-576=0
Subtract 576 from both sides.
-207,36+b^{2}=0
Subtract 576 from 368,64 to get -207,36.
\left(b-\frac{72}{5}\right)\left(b+\frac{72}{5}\right)=0
Consider -207,36+b^{2}. Rewrite -207,36+b^{2} as b^{2}-\left(\frac{72}{5}\right)^{2}. The difference of squares can be factored using the rule: a^{2}-b^{2}=\left(a-b\right)\left(a+b\right).
b=\frac{72}{5} b=-\frac{72}{5}
To find equation solutions, solve b-\frac{72}{5}=0 and b+\frac{72}{5}=0.
368,64+b^{2}=24^{2}
Calculate 19,2 to the power of 2 and get 368,64.
368,64+b^{2}=576
Calculate 24 to the power of 2 and get 576.
b^{2}=576-368,64
Subtract 368,64 from both sides.
b^{2}=207,36
Subtract 368,64 from 576 to get 207,36.
b=\frac{72}{5} b=-\frac{72}{5}
Take the square root of both sides of the equation.
368,64+b^{2}=24^{2}
Calculate 19,2 to the power of 2 and get 368,64.
368,64+b^{2}=576
Calculate 24 to the power of 2 and get 576.
368,64+b^{2}-576=0
Subtract 576 from both sides.
-207,36+b^{2}=0
Subtract 576 from 368,64 to get -207,36.
b^{2}-207,36=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.
b=\frac{0±\sqrt{0^{2}-4\left(-207,36\right)}}{2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, 0 for b, and -207,36 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
b=\frac{0±\sqrt{-4\left(-207,36\right)}}{2}
Square 0.
b=\frac{0±\sqrt{829,44}}{2}
Multiply -4 times -207,36.
b=\frac{0±\frac{144}{5}}{2}
Take the square root of 829,44.
b=\frac{72}{5}
Now solve the equation b=\frac{0±\frac{144}{5}}{2} when ± is plus.
b=-\frac{72}{5}
Now solve the equation b=\frac{0±\frac{144}{5}}{2} when ± is minus.
b=\frac{72}{5} b=-\frac{72}{5}
The equation is now solved.
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