2x - 1y = -9
y = - 5 - 5x

Evaluate the expression for the given value of the variable 7a - 4a for a =8

Write the fraction or mixed number and the decimal shown by the model

Is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis.