I need help it's late

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?

What is the base of the exponential expression of 4 to the power of 5

7x^2-9x+5=0 find the discriminant and number of real solutions