Which of the following inequalities is true?

If f(x)=2x-6 and g(x)=3x+9, find (f-g)(x)

Solve for x and y: 217x + 131y = 913; 131x + 217y = 827

Look at the figure below: triangle abc is a right triangle with angle abc equal to 90 degrees. the length of ac is 5 units and the length of ab is 4 units. d is a point above c. triangle adc is a right triangle with angle dac equal to 90 degrees and dc parallel to ab. what is the length, in units, of segment cd?