How do i solve this quadratic equations by factoring

3× __ -2=15 7 2× __+1=7 5 7× =22 15 5× __+10=2 8 × __+4=20 6 × =10 3 × __+2=8 6 × __+8=8 9 × __+7=20 6

Ineed with number 6 , explain how to get 1978

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?