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x=-2
x=2
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12\times \left(\frac{x+1}{2}\right)^{2}=2\times 3x+15
Multiply both sides of the equation by 12, the least common multiple of 3,2,4.
12\times \frac{\left(x+1\right)^{2}}{2^{2}}=2\times 3x+15
To raise \frac{x+1}{2} to a power, raise both numerator and denominator to the power and then divide.
\frac{12\left(x+1\right)^{2}}{2^{2}}=2\times 3x+15
Express 12\times \frac{\left(x+1\right)^{2}}{2^{2}} as a single fraction.
\frac{12\left(x+1\right)^{2}}{2^{2}}=6x+15
Multiply 2 and 3 to get 6.
\frac{12\left(x^{2}+2x+1\right)}{2^{2}}=6x+15
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(x+1\right)^{2}.
\frac{12\left(x^{2}+2x+1\right)}{4}=6x+15
Calculate 2 to the power of 2 and get 4.
3\left(x^{2}+2x+1\right)=6x+15
Divide 12\left(x^{2}+2x+1\right) by 4 to get 3\left(x^{2}+2x+1\right).
3x^{2}+6x+3=6x+15
Use the distributive property to multiply 3 by x^{2}+2x+1.
3x^{2}+6x+3-6x=15
Subtract 6x from both sides.
3x^{2}+3=15
Combine 6x and -6x to get 0.
3x^{2}+3-15=0
Subtract 15 from both sides.
3x^{2}-12=0
Subtract 15 from 3 to get -12.
x^{2}-4=0
Divide both sides by 3.
\left(x-2\right)\left(x+2\right)=0
Consider x^{2}-4. Rewrite x^{2}-4 as x^{2}-2^{2}. The difference of squares can be factored using the rule: a^{2}-b^{2}=\left(a-b\right)\left(a+b\right).
x=2 x=-2
To find equation solutions, solve x-2=0 and x+2=0.
12\times \left(\frac{x+1}{2}\right)^{2}=2\times 3x+15
Multiply both sides of the equation by 12, the least common multiple of 3,2,4.
12\times \frac{\left(x+1\right)^{2}}{2^{2}}=2\times 3x+15
To raise \frac{x+1}{2} to a power, raise both numerator and denominator to the power and then divide.
\frac{12\left(x+1\right)^{2}}{2^{2}}=2\times 3x+15
Express 12\times \frac{\left(x+1\right)^{2}}{2^{2}} as a single fraction.
\frac{12\left(x+1\right)^{2}}{2^{2}}=6x+15
Multiply 2 and 3 to get 6.
\frac{12\left(x^{2}+2x+1\right)}{2^{2}}=6x+15
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(x+1\right)^{2}.
\frac{12\left(x^{2}+2x+1\right)}{4}=6x+15
Calculate 2 to the power of 2 and get 4.
3\left(x^{2}+2x+1\right)=6x+15
Divide 12\left(x^{2}+2x+1\right) by 4 to get 3\left(x^{2}+2x+1\right).
3x^{2}+6x+3=6x+15
Use the distributive property to multiply 3 by x^{2}+2x+1.
3x^{2}+6x+3-6x=15
Subtract 6x from both sides.
3x^{2}+3=15
Combine 6x and -6x to get 0.
3x^{2}=15-3
Subtract 3 from both sides.
3x^{2}=12
Subtract 3 from 15 to get 12.
x^{2}=\frac{12}{3}
Divide both sides by 3.
x^{2}=4
Divide 12 by 3 to get 4.
x=2 x=-2
Take the square root of both sides of the equation.
12\times \left(\frac{x+1}{2}\right)^{2}=2\times 3x+15
Multiply both sides of the equation by 12, the least common multiple of 3,2,4.
12\times \frac{\left(x+1\right)^{2}}{2^{2}}=2\times 3x+15
To raise \frac{x+1}{2} to a power, raise both numerator and denominator to the power and then divide.
\frac{12\left(x+1\right)^{2}}{2^{2}}=2\times 3x+15
Express 12\times \frac{\left(x+1\right)^{2}}{2^{2}} as a single fraction.
\frac{12\left(x+1\right)^{2}}{2^{2}}=6x+15
Multiply 2 and 3 to get 6.
\frac{12\left(x^{2}+2x+1\right)}{2^{2}}=6x+15
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(x+1\right)^{2}.
\frac{12\left(x^{2}+2x+1\right)}{4}=6x+15
Calculate 2 to the power of 2 and get 4.
3\left(x^{2}+2x+1\right)=6x+15
Divide 12\left(x^{2}+2x+1\right) by 4 to get 3\left(x^{2}+2x+1\right).
3x^{2}+6x+3=6x+15
Use the distributive property to multiply 3 by x^{2}+2x+1.
3x^{2}+6x+3-6x=15
Subtract 6x from both sides.
3x^{2}+3=15
Combine 6x and -6x to get 0.
3x^{2}+3-15=0
Subtract 15 from both sides.
3x^{2}-12=0
Subtract 15 from 3 to get -12.
x=\frac{0±\sqrt{0^{2}-4\times 3\left(-12\right)}}{2\times 3}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 3 for a, 0 for b, and -12 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\times 3\left(-12\right)}}{2\times 3}
Square 0.
x=\frac{0±\sqrt{-12\left(-12\right)}}{2\times 3}
Multiply -4 times 3.
x=\frac{0±\sqrt{144}}{2\times 3}
Multiply -12 times -12.
x=\frac{0±12}{2\times 3}
Take the square root of 144.
x=\frac{0±12}{6}
Multiply 2 times 3.
x=2
Now solve the equation x=\frac{0±12}{6} when ± is plus. Divide 12 by 6.
x=-2
Now solve the equation x=\frac{0±12}{6} when ± is minus. Divide -12 by 6.
x=2 x=-2
The equation is now solved.
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