Algebra 2 Common Core

Published by Prentice Hall
ISBN 10: 0133186024
ISBN 13: 978-0-13318-602-4

Chapter 4 - Quadratic Functions and Equations - 4-6 Complete the Square - Practice and Problem-Solving Exercises - Page 239: 90

Answer

The solutions are $x = \frac{1}{2}$ and $x = 1$.

Work Step by Step

We have a quadratic equation, which is in the form $ax^2 + bx + c = 0$. To factor the quadratic trinomial, look for the factors of the product $ac$ that when added together equals $b$. The trinomial has $ac=2(1)=2$ and $b=-3$. The product is positive while the sum is negative. This means that both factors must be negative. Thus, the only possible factors are: $-2$ and $-1$ (note that the sum is $-3$) Rewrite the middle term of the trinomial using $-2$ and $-1$ to obtain: $$2x^2 - 2x - x + 1 = 0$$ Group the first two terms together and group the last two terms together: $$(2x^2 - 2x) + (-x - 1) = 0$$ Factor out the GCF in the first group and factor out $-1$ in the second group: $$2x(x - 1) + (-1)(x - 1) = 0$$ Factor the GCF of the two groups, which is $x-1$: $$(2x - 1)(x - 1) = 0$$ Solve the equation using the Zero-Product Property by equating each factor to $0$, then solve each equation. First factor: $2x - 1 = 0$ $2x = 1$ Divide each side by $2$: $x = \frac{1}{2}$ Second factor: $x - 1 = 0$ $x = 1$ The solutions are $x = \frac{1}{2}$ and $x = 1$.
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