SOLUTION: find the number of solutions of 5x^2-10x-8=0 by using the discriminant. Help please, show work please and thanks.

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Question 870815: find the number of solutions of 5x^2-10x-8=0 by using the discriminant.
Help please, show work please and thanks.

Found 2 solutions by ewatrrr, richwmiller:
Answer by ewatrrr(24785)   (Show Source): You can put this solution on YOUR website!

discriminant is
5x^2-10x-8=0

Two real solutions
y = 5(x-1)^2 -13

Answer by richwmiller(17219)   (Show Source): You can put this solution on YOUR website!
Solved by pluggable solver: Quadratic Formula
Let's use the quadratic formula to solve for x:


Starting with the general quadratic





the general solution using the quadratic equation is:







So lets solve ( notice , , and )





Plug in a=5, b=-10, and c=-8




Negate -10 to get 10




Square -10 to get 100 (note: remember when you square -10, you must square the negative as well. This is because .)




Multiply to get




Combine like terms in the radicand (everything under the square root)




Simplify the square root (note: If you need help with simplifying the square root, check out this solver)




Multiply 2 and 5 to get 10


So now the expression breaks down into two parts


or



Now break up the fraction



or



Simplify



or



So the solutions are:

or



the discriminant is 260
which tells us there are 2 real solutions

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