1. The difference between the measure of an angle and its complementary angle is 10°. Find the measure of the greater angle.

3. Find the value of D for the equations: y + 2x = 19 and 2x − 3y = − 3.

5. If (2, − 5) is the solution of the equation 2x − ky = 14, then k ?

7. Check whether x = 2 and y = − 1 is a solution of the equation 2x + y = 3.

9. If 52x + 65y = 183 and 65x + 52y = 168, then find x + y.