Pls help me on this question

Here take some candy:

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?

Mon wants to make 5 lbs of the sugar syrup. how much water and how much sugar does he need… …to make 5% syrup?

Solve the system of equations. x=-2y+1 and x+2y=9. show work