Question

Find the x intercept 0= -.00013x^2+ x+ 10

Answer 1

0 = -0.00013x^2 + x + 10
0.00013x^2 - x - 10 = 0
13x^2 - 100000x - 1000000 = 0
$x= \frac{-b\pm\sqrt{b^2-4ac}}{2a}$; where a = 13, b = -100000 and c = -1000000
$x=\frac{-(-100000)\pm\sqrt{(-100000)^2-(4\times13\times(-1000000))}}{2\times13}\\=\frac{100000\pm\sqrt{10000000000+52000000}}{26}=\frac{100000\pm\sqrt{10052000000}}{26}\\=\frac{100000\pm\sqrt{4000000\times2513}}{26}=\frac{100000\pm2000\sqrt{2513}}{26}$
x = 7702 or x = -10