Which of the following statements is true? Before Jenner's vaccine, there was no prevention for smallpox.
Edward Jenner developed the first vaccine for cowpox.
Vaccination is only necessary for children under 5 years old.
Missed vaccinations can be given during "catch-up" periods.

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?

Whoever gets this right gets the ! the half life of a soul smelling substance is 4 years. if you have 8 oz of this strange substance, how much of it will you have after 20 years? show work.

Lines a and b are perpendicular. if the slope of line a is 3, what is the slope of line b?