Question

Solve using the quadratic formula.

x² + x = 12

Answer 1

a = 1
b = 2
c = -12

Use these values and insert those in quadratic formula.

Answer 2

http://2.bp.blogspot.com/_9xX2yNGJA4E/TPm214sFVjI/AAAAAAAAADI/nVLP-mPhYCM/s1600/QuadraticFormula.JPG

Answer 3

\[\Large x^2 + x = 12\]


\[\Large x^2 + x - 12 = 0\]


Now use the quadratic formula to solve for x


\[\Large x = \frac{-b\pm\sqrt{b^2-4ac}}{2a}\]


\[\Large x = \frac{-(1)\pm\sqrt{(1)^2-4(1)(-12)}}{2(1)}\]


\[\Large x = \frac{-1\pm\sqrt{1-(-48)}}{2}\]


\[\Large x = \frac{-1\pm\sqrt{49}}{2}\]


\[\Large x = \frac{-1+\sqrt{49}}{2} \ \text{or} \ x = \frac{-1-\sqrt{49}}{2}\]


\[\Large x = \frac{-1+7}{2} \ \text{or} \ x = \frac{-1-7}{2}\]


\[\Large x = \frac{6}{2} \ \text{or} \ x = \frac{-8}{2}\]


\[\Large x = 3 \ \text{or} \ x = -4\]


So the solutions are \[\Large x = 3 \ \text{or} \ x = -4\]

Answer 4

@jim_thompson5910 best answer I've seen so far ! well done !