Question 160182
√2(9 √5 - 7 √9)=

Use the distributive rule.

Do you remember what that is?

Here is the basic idea:

This means to multiply every number or term that lies inside the parentheses by the number or term that is outside the parentheses.

√2 times (9√5) = 9√10

√2 times (-7√9) = -7√18

We have now removed the parentheses.  This is the main reason why we use the distributive rule.

We now have this:

9√10 - 7√18 =

Do you see √18?

We can break this radical down.

√9 times √2 = 3√2

We now have this:

9√10 - 7(3√2) = 9√10 - 21√2

We cannot break this question down anymore.

Final answer:  9√10 - 21√2