Skip to main content
Solve for x
Tick mark Image
Graph

Similar Problems from Web Search

Share

160=14x+13x+x^{2}
Use the distributive property to multiply 13+x by x.
160=27x+x^{2}
Combine 14x and 13x to get 27x.
27x+x^{2}=160
Swap sides so that all variable terms are on the left hand side.
27x+x^{2}-160=0
Subtract 160 from both sides.
x^{2}+27x-160=0
All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. The quadratic formula gives two solutions, one when ± is addition and one when it is subtraction.
x=\frac{-27±\sqrt{27^{2}-4\left(-160\right)}}{2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, 27 for b, and -160 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-27±\sqrt{729-4\left(-160\right)}}{2}
Square 27.
x=\frac{-27±\sqrt{729+640}}{2}
Multiply -4 times -160.
x=\frac{-27±\sqrt{1369}}{2}
Add 729 to 640.
x=\frac{-27±37}{2}
Take the square root of 1369.
x=\frac{10}{2}
Now solve the equation x=\frac{-27±37}{2} when ± is plus. Add -27 to 37.
x=5
Divide 10 by 2.
x=-\frac{64}{2}
Now solve the equation x=\frac{-27±37}{2} when ± is minus. Subtract 37 from -27.
x=-32
Divide -64 by 2.
x=5 x=-32
The equation is now solved.
160=14x+13x+x^{2}
Use the distributive property to multiply 13+x by x.
160=27x+x^{2}
Combine 14x and 13x to get 27x.
27x+x^{2}=160
Swap sides so that all variable terms are on the left hand side.
x^{2}+27x=160
Quadratic equations such as this one can be solved by completing the square. In order to complete the square, the equation must first be in the form x^{2}+bx=c.
x^{2}+27x+\left(\frac{27}{2}\right)^{2}=160+\left(\frac{27}{2}\right)^{2}
Divide 27, the coefficient of the x term, by 2 to get \frac{27}{2}. Then add the square of \frac{27}{2} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}+27x+\frac{729}{4}=160+\frac{729}{4}
Square \frac{27}{2} by squaring both the numerator and the denominator of the fraction.
x^{2}+27x+\frac{729}{4}=\frac{1369}{4}
Add 160 to \frac{729}{4}.
\left(x+\frac{27}{2}\right)^{2}=\frac{1369}{4}
Factor x^{2}+27x+\frac{729}{4}. 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(x+\frac{27}{2}\right)^{2}}=\sqrt{\frac{1369}{4}}
Take the square root of both sides of the equation.
x+\frac{27}{2}=\frac{37}{2} x+\frac{27}{2}=-\frac{37}{2}
Simplify.
x=5 x=-32
Subtract \frac{27}{2} from both sides of the equation.