What algebraic expression must be subtracted from the sum of y^2 + 5y -1 and 3y^2-2y+4 to give 2y^2+7y-2 as the result

The reflexive property of congruence lets you say that ∠pqr ≅

Which of the following statements is true? a. the irrational number system is not closed under multiplication, because the product of two irrational numbers is always a rational number. b. the irrational number system is not closed under multiplication, because the product of two irrational numbers is not always an irrational number. c. the irrational number system is closed under multiplication, because the product of two irrational numbers is always an irrational number. d. the irrational number system is closed under multiplication, because the product of two irrational numbers is always a rational numbers. reset submit

Is experimental probibilty the same as the observed frequency in math? i need the answer asap!