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Find n if log$$_2$$ 4 + log$$_2$$ 7 — log$$_2$$ n = 1

Question

Find n if log$$_2$$ 4 + log$$_2$$ 7 — log$$_2$$ n = 1

A)
10
B)
14
C)
27
D)
28

Explanation:

$$\log_2 4 + \log_2 7 - \log_2 n = 1$$
$$\log_2 \left( \cfrac{4 \times 2}{n} \right) = 1$$
$$\log_2 \cfrac{28}{n} = 1$$
$$2^1 = \cfrac{28}{n}$$
$$2n = 28$$
$$n = 14$$

Discussion (2)

• $$\log_2 4 + \log_2 7 - \log_2 n = 1$$
$$\log_2 \left( \cfrac{4 \times 2}{n} \right) = 1$$
$$\log_2 \cfrac{28}{n} = 1$$
$$2^1 = \cfrac{28}{n}$$
$$2n = 28$$
$$n = 14$$