Question

8.4 add, subtract, and multiply radical expressions
score: 7.8/22 answered: 8/22
question 9
simplify.
3\sqrt{12b}+5\sqrt{45b}=
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Explanation:

Step1: Simplify $\sqrt{12b}$

We know that $12b = 4\times3b$, so $\sqrt{12b}=\sqrt{4\times3b}=2\sqrt{3b}$. Then $3\sqrt{12b}=3\times2\sqrt{3b}=6\sqrt{3b}$.

Step2: Simplify $\sqrt{45b}$

Since $45b = 9\times5b$, then $\sqrt{45b}=\sqrt{9\times5b}=3\sqrt{5b}$. And $5\sqrt{45b}=5\times3\sqrt{5b}=15\sqrt{5b}$.

Step3: Combine the results

$3\sqrt{12b}+5\sqrt{45b}=6\sqrt{3b}+15\sqrt{5b}$.

Answer:

$6\sqrt{3b}+15\sqrt{5b}$