SOLUTION: Solve by using the quadratic formula. 2x^2 + 5x = 4

Question 88257: Solve by using the quadratic formula. 2x^2 + 5x = 4

Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!

Subtract 4 from both sides

Now let's use the quadratic formula to solve for x:

Starting with the general quadratic

the general form of the quadratic equation is:

So lets solve (notice , , and )

Plug in a=2, b=5, and c=-4

Square 5 to get 25

Multiply to get

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

Simplify the square root

Multiply 2 and 2 to get 4

So now the expression breaks down into two parts

or

Which approximate to

or

So our solutions are:
or

Notice when we graph we get:

when we use the root finder feature on a calculator, we find that and .So this verifies our answer

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