What is the solution of the system? use substitution.
3x + 2y = 7
y = –3x + 11
a. (6, -3)
b. (6, -7)
c. (-4 19/2)
d. (5, -4)

Two planes leave an airport at the same time, one flying east, the other flying west. the eastbound plane travels 20 mph slower. they are 1600 mi apart after 2 hr. find the speed of each plane.

45% of the trees in a park are apple trees. there are 27 apple trees in the park. how many trees are in the park in all?

Segment an is an altitude of right δabc with a right angle at a. if ab = 2, squared 5 in and nc = 1 in, find bn, an, ac.