Solve the system by substitution.

$-2x-5y=3$

$3x+8y=-6$

Find the value of x for which abcd must be a parallelogram -9-6x x-30

Last month, a 770 g box of cereal was sold at a grocery store for $3.10. however, this month, the cereal manufacturer launched the same cereal in a 640 g box, which is being sold at $2.50. what is the percent change in the unit price?

Are the corresponding angles congruent? explain why or why not.