What is the coefficient of the x4-term in the binomial expansion of (x + 3)12? 12C7(3)7
12C8
12C4(3)4
12C8(3)8

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?