1. Solve for   x,   and check.

2x2 + 3x = 20

This is a quadratic equation so we run through the steps for solving quadratic equations.

Transpose all terms to one side leaving a zero on the other.

2x2 + 3x - 20 = 0

Factor

(2x - 5)(x + 4) = 0

Set the factors = 0, and solve the resulting equations.

check

Let   x = 5/2.   Then the equation becomes

Do the power first

Next multiply

Add the fractions on the left. Note that we have common denominators.

which checks.

Next let   x = -4.   The equation becomes

2(4)2 + 3(-4) = 2-

Do the power first.

2(16) + 3(-4) = 20

Then multiply.

32 - 12 = 20

which checks.

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