The mistake made by Abby in solving the quadratic equation was at Step 2, in which she did not simplify her answer correctly.
A quadratic equation is modeled by:
[tex]y = ax^2 + bx + c[/tex]
The solutions are given by:
[tex]x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}[/tex]
In this problem, Abby substituted correctly, but at the simplification, she made a mistake in the signal, as:
[tex](-6)^2 - 4(5)(-8) = 36 + 160[/tex]
Hence the mistake was in Step 2.
More can be learned about quadratic equations at https://brainly.com/question/24737967
Step 2 is not correct, she did not simplify under the square root correctly.
An equation is an expression that shows the relationship between two or more variables and numbers.
Given the equation:
5x² - 6x - 8 = 0
a = 5, b = -6 and c = -8
From the equation:
[tex]x=\frac{-b \pm \sqrt{b^2-4ac} }{2a} \\\\Step\ 1:x=\frac{-(-6) \pm \sqrt{(-6)^2-4(5)(-8)} }{2(5)} \\\\Step\ 2:x=\frac{6\pm \sqrt{36+160} }{10}\\\\Step\ 3: x=-0.8\ AND\ x=2[/tex]
Step 2 is not correct, she did not simplify under the square root correctly.
find out more on equation at: https://brainly.com/question/2972832