Which expression is equivalent to 10c-6c+3+7d+12+4d

Lisa has three classes that each last 50 minutes. what is the total number of minutes of the three classes

What describes horizontal cross section of the right rectangle 6m 8m 5m

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?