Skip to main content
Solve for a
Tick mark Image

Similar Problems from Web Search

Share

7a^{2}=\left(a-1\right)a
Variable a cannot be equal to 1 since division by zero is not defined. Multiply both sides of the equation by 7\left(a-1\right)^{2}, the least common multiple of \left(a-1\right)^{2},7\left(a-1\right).
7a^{2}=a^{2}-a
Use the distributive property to multiply a-1 by a.
7a^{2}-a^{2}=-a
Subtract a^{2} from both sides.
6a^{2}=-a
Combine 7a^{2} and -a^{2} to get 6a^{2}.
6a^{2}+a=0
Add a to both sides.
a\left(6a+1\right)=0
Factor out a.
a=0 a=-\frac{1}{6}
To find equation solutions, solve a=0 and 6a+1=0.
7a^{2}=\left(a-1\right)a
Variable a cannot be equal to 1 since division by zero is not defined. Multiply both sides of the equation by 7\left(a-1\right)^{2}, the least common multiple of \left(a-1\right)^{2},7\left(a-1\right).
7a^{2}=a^{2}-a
Use the distributive property to multiply a-1 by a.
7a^{2}-a^{2}=-a
Subtract a^{2} from both sides.
6a^{2}=-a
Combine 7a^{2} and -a^{2} to get 6a^{2}.
6a^{2}+a=0
Add a to both sides.
a=\frac{-1±\sqrt{1^{2}}}{2\times 6}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 6 for a, 1 for b, and 0 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
a=\frac{-1±1}{2\times 6}
Take the square root of 1^{2}.
a=\frac{-1±1}{12}
Multiply 2 times 6.
a=\frac{0}{12}
Now solve the equation a=\frac{-1±1}{12} when ± is plus. Add -1 to 1.
a=0
Divide 0 by 12.
a=-\frac{2}{12}
Now solve the equation a=\frac{-1±1}{12} when ± is minus. Subtract 1 from -1.
a=-\frac{1}{6}
Reduce the fraction \frac{-2}{12} to lowest terms by extracting and canceling out 2.
a=0 a=-\frac{1}{6}
The equation is now solved.
7a^{2}=\left(a-1\right)a
Variable a cannot be equal to 1 since division by zero is not defined. Multiply both sides of the equation by 7\left(a-1\right)^{2}, the least common multiple of \left(a-1\right)^{2},7\left(a-1\right).
7a^{2}=a^{2}-a
Use the distributive property to multiply a-1 by a.
7a^{2}-a^{2}=-a
Subtract a^{2} from both sides.
6a^{2}=-a
Combine 7a^{2} and -a^{2} to get 6a^{2}.
6a^{2}+a=0
Add a to both sides.
\frac{6a^{2}+a}{6}=\frac{0}{6}
Divide both sides by 6.
a^{2}+\frac{1}{6}a=\frac{0}{6}
Dividing by 6 undoes the multiplication by 6.
a^{2}+\frac{1}{6}a=0
Divide 0 by 6.
a^{2}+\frac{1}{6}a+\left(\frac{1}{12}\right)^{2}=\left(\frac{1}{12}\right)^{2}
Divide \frac{1}{6}, the coefficient of the x term, by 2 to get \frac{1}{12}. Then add the square of \frac{1}{12} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
a^{2}+\frac{1}{6}a+\frac{1}{144}=\frac{1}{144}
Square \frac{1}{12} by squaring both the numerator and the denominator of the fraction.
\left(a+\frac{1}{12}\right)^{2}=\frac{1}{144}
Factor a^{2}+\frac{1}{6}a+\frac{1}{144}. 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(a+\frac{1}{12}\right)^{2}}=\sqrt{\frac{1}{144}}
Take the square root of both sides of the equation.
a+\frac{1}{12}=\frac{1}{12} a+\frac{1}{12}=-\frac{1}{12}
Simplify.
a=0 a=-\frac{1}{6}
Subtract \frac{1}{12} from both sides of the equation.