Question

for the few questions in this set, you will see the quadratic formula. soon, you will need to answer the questions without this reminder.
$x = \frac{ -b \pm \sqrt{b^2 - 4ac} }{ 2a }$
for $ax^2 + bx + c = 0$

solve for x. write both solutions, separated by a comma.
$5x^2 + x - 4 = 0$
enter the correct answer.

Explanation:

Step1: Identify a, b, c values

$a=5,\ b=1,\ c=-4$

Step2: Compute discriminant

$\sqrt{b^2-4ac} = \sqrt{1^2 - 4(5)(-4)} = \sqrt{1+80} = \sqrt{81}=9$

Step3: Apply quadratic formula

$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a} = \frac{-1\pm9}{10}$

Step4: Calculate two solutions

$x_1=\frac{-1+9}{10}=\frac{8}{10}=\frac{4}{5}$
$x_2=\frac{-1-9}{10}=\frac{-10}{10}=-1$

Answer:

$x=-1,\ x=\frac{4}{5}$