(matrix) addiction and subtraction of a matrix

calculate:
a) a+b+c
b) a-b-c
c) a+b-c

Flashback to semester a. are triangles pqr and stu congruent? what is the congruency that proves they are congruent? what is the perimeter of triangle pqr? show your work.

The parabola y = x² - 4 opens: a.) up b.) down c.) right d.) left

The length of a rectangular piece of land is 92 yards more than three times its width. the perimeter is 760 yards. find its dimensions.