Solve for t
t=\frac{2\sqrt{15}}{3}-1\approx 1.581988897
t=-\frac{2\sqrt{15}}{3}-1\approx -3.581988897
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15-\left(2-3\right)=3\left(t+1\right)^{2}-\left(3+1\right)
Multiply both sides of the equation by 3.
15-\left(-1\right)=3\left(t+1\right)^{2}-\left(3+1\right)
Subtract 3 from 2 to get -1.
15+1=3\left(t+1\right)^{2}-\left(3+1\right)
The opposite of -1 is 1.
16=3\left(t+1\right)^{2}-\left(3+1\right)
Add 15 and 1 to get 16.
16=3\left(t^{2}+2t+1\right)-\left(3+1\right)
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(t+1\right)^{2}.
16=3t^{2}+6t+3-\left(3+1\right)
Use the distributive property to multiply 3 by t^{2}+2t+1.
16=3t^{2}+6t+3-4
Add 3 and 1 to get 4.
16=3t^{2}+6t-1
Subtract 4 from 3 to get -1.
3t^{2}+6t-1=16
Swap sides so that all variable terms are on the left hand side.
3t^{2}+6t-1-16=0
Subtract 16 from both sides.
3t^{2}+6t-17=0
Subtract 16 from -1 to get -17.
t=\frac{-6±\sqrt{6^{2}-4\times 3\left(-17\right)}}{2\times 3}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 3 for a, 6 for b, and -17 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
t=\frac{-6±\sqrt{36-4\times 3\left(-17\right)}}{2\times 3}
Square 6.
t=\frac{-6±\sqrt{36-12\left(-17\right)}}{2\times 3}
Multiply -4 times 3.
t=\frac{-6±\sqrt{36+204}}{2\times 3}
Multiply -12 times -17.
t=\frac{-6±\sqrt{240}}{2\times 3}
Add 36 to 204.
t=\frac{-6±4\sqrt{15}}{2\times 3}
Take the square root of 240.
t=\frac{-6±4\sqrt{15}}{6}
Multiply 2 times 3.
t=\frac{4\sqrt{15}-6}{6}
Now solve the equation t=\frac{-6±4\sqrt{15}}{6} when ± is plus. Add -6 to 4\sqrt{15}.
t=\frac{2\sqrt{15}}{3}-1
Divide -6+4\sqrt{15} by 6.
t=\frac{-4\sqrt{15}-6}{6}
Now solve the equation t=\frac{-6±4\sqrt{15}}{6} when ± is minus. Subtract 4\sqrt{15} from -6.
t=-\frac{2\sqrt{15}}{3}-1
Divide -6-4\sqrt{15} by 6.
t=\frac{2\sqrt{15}}{3}-1 t=-\frac{2\sqrt{15}}{3}-1
The equation is now solved.
15-\left(2-3\right)=3\left(t+1\right)^{2}-\left(3+1\right)
Multiply both sides of the equation by 3.
15-\left(-1\right)=3\left(t+1\right)^{2}-\left(3+1\right)
Subtract 3 from 2 to get -1.
15+1=3\left(t+1\right)^{2}-\left(3+1\right)
The opposite of -1 is 1.
16=3\left(t+1\right)^{2}-\left(3+1\right)
Add 15 and 1 to get 16.
16=3\left(t^{2}+2t+1\right)-\left(3+1\right)
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(t+1\right)^{2}.
16=3t^{2}+6t+3-\left(3+1\right)
Use the distributive property to multiply 3 by t^{2}+2t+1.
16=3t^{2}+6t+3-4
Add 3 and 1 to get 4.
16=3t^{2}+6t-1
Subtract 4 from 3 to get -1.
3t^{2}+6t-1=16
Swap sides so that all variable terms are on the left hand side.
3t^{2}+6t=16+1
Add 1 to both sides.
3t^{2}+6t=17
Add 16 and 1 to get 17.
\frac{3t^{2}+6t}{3}=\frac{17}{3}
Divide both sides by 3.
t^{2}+\frac{6}{3}t=\frac{17}{3}
Dividing by 3 undoes the multiplication by 3.
t^{2}+2t=\frac{17}{3}
Divide 6 by 3.
t^{2}+2t+1^{2}=\frac{17}{3}+1^{2}
Divide 2, the coefficient of the x term, by 2 to get 1. Then add the square of 1 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
t^{2}+2t+1=\frac{17}{3}+1
Square 1.
t^{2}+2t+1=\frac{20}{3}
Add \frac{17}{3} to 1.
\left(t+1\right)^{2}=\frac{20}{3}
Factor t^{2}+2t+1. In general, when x^{2}+bx+c is a perfect square, it can always be factored as \left(x+\frac{b}{2}\right)^{2}.
\sqrt{\left(t+1\right)^{2}}=\sqrt{\frac{20}{3}}
Take the square root of both sides of the equation.
t+1=\frac{2\sqrt{15}}{3} t+1=-\frac{2\sqrt{15}}{3}
Simplify.
t=\frac{2\sqrt{15}}{3}-1 t=-\frac{2\sqrt{15}}{3}-1
Subtract 1 from both sides of the equation.
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Limits
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