Solve the system of equations using matrices. use gaussian elimination with back-substitution.    x + y + z      =      -5  x - y + 3z     =     -1  4x + y + z    =     -2 

Tim's phone service charges $23.06 plus an additional $0.22 for each text message sent per month. if tim's phone bill was $28.56, which equation could be used to find how many text messages, x, tim sent last month?

Thee blue triangle has rotated from quadrant i to quadrant iii about the origin. describe the effects of the rotation on the coordinates of the blue triangle.

Percent increase and decrease. original number: 45 new number: 18