Question
Solve the following equations for the unknown: $(a + 2)(2a +5) = 2(a + 1)^2+ 13$
✓
Answer
$(a + 2)(2a +5) = 2(a + 1)^2+ 13$
Collecting like terms,
$\Rightarrow a(2a + 5) + 2 (2a + 5) = 2a^2 + 2 + 4a + 13$
$\Rightarrow 2a^2+ 5a + 4a + 10 - (2a^2+ 4a + 15) = 0$
$\Rightarrow 5a + 10 - 15 = 0$
$\Rightarrow a = 1$ is the unknown.
Collecting like terms,
$\Rightarrow a(2a + 5) + 2 (2a + 5) = 2a^2 + 2 + 4a + 13$
$\Rightarrow 2a^2+ 5a + 4a + 10 - (2a^2+ 4a + 15) = 0$
$\Rightarrow 5a + 10 - 15 = 0$
$\Rightarrow a = 1$ is the unknown.
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