8. Alice is 7 years younger than Bob. In 4 years time she will be half Bob’s age. Let Alice’s age be a and Bob’s b. a) Use the first sentence write an equation for Alice’s age in terms of Bob’s.

b) Use the second sentence to write another equation for Alice’s age in terms of Bob’s.

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?