Question

select the correct answer.
what is this expression in simplified form?
$(6\sqrt{2})\\ (-3\sqrt{5})$
a. $-90$
b. $-18\sqrt{10}$
c. $-18\sqrt{7}$
d. $3\sqrt{7}$

Explanation:

Step1: Multiply the coefficients

Multiply 6 and -3.
$6\times(-3) = -18$

Step2: Multiply the radicals

Multiply $\sqrt{2}$ and $\sqrt{5}$ using the property $\sqrt{a}\times\sqrt{b}=\sqrt{ab}$.
$\sqrt{2}\times\sqrt{5}=\sqrt{2\times5}=\sqrt{10}$

Step3: Combine the results

Multiply the result from Step1 and Step2.
$-18\times\sqrt{10}=-18\sqrt{10}$

Answer:

B. $-18\sqrt{10}$