Question

Solve the following equation and give your answer correct to 3 significant figures:

$5x^2-3x-4=0$

Answer 1

$5x^2-3x-4=0$

Here, $a=5,b=-3,c=-4$

So, $x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}=\frac{3\pm \sqrt{(-3{)}^2-4\times 5\times (-4)}}{2\times 5}=\frac{3\pm \sqrt{80}}{10}=\frac{3\pm 9.434}{10}\Rightarrow x=12.434orx=-0.643$