Ineed to simplify (4a^3+7a^2b+6b^3) + (a^3+2a^2b+4b^3)

At $1.32 million, they closed last month percent above what they paid in 2007." how much did they pay in 2007?

Can someone me out here number 4 plz

1- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis.2- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in the first question?