2 cos^215° - 1
use a double angle identity to find the exact value of the expression

What is the size of the matrix resulting from

Δabc is dilated by a scale factor of 3 with the origin as the center of dilation to form δa′b′c′. the slope of is -1.2. the length of is p units, the length of is q units, and the length of is r units. the slope of is . the length of is units.

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10