Question

Use substitution to write an equivalent quadratic equation.

(3x + 2)2 + 7(3x + 2) - 8 = 0
DONE

Answer 1

z^2 +7z -8 = 0

Explanation:

Let z = 3x+2. Then we can substitute z wherever we see 3x+2.

z^2 +7z -8 = 0 . . . . equivalent quadratic

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This is easily factored to ...

(z -1)(z +8) = 0

So, the original quadratic has solutions ...

(3x +2) -1 = 0

x = -1/3

and

(3x +2) +8 = 0

x = -10/3