What is the difference of the two polynomials?

(7y2 + 6xy) – (–2xy + 3)
a7y2 + 4xy – 3
b7y2 + 8xy – 3
c7y2 + 4xy + 3
d7y2 + 8xy + 3

In triangle abc, the length of side ab is 12 cm, the length of side bc is 5 cm, and the length of side ca is 9 cm. find the measure of angle a using the law of cosines.

What is the distance between (–2 1/2,-3) and (1, –3)?

Change negative exponents to positive. then solve. round to four decimal places