7) The bisected angle in the first triangle will always set up this relationship
10 / 24 = ? / 36
5/12 = ? / 36 cross - multiply
36 * 5 = 12 * ?
180 = 12 * ? divide both sides by 12
15 = ?
8) Similarly
[ 5x - 6 ] / 42 = 28 / 49
[ 5x - 6 ] / 42 = 4 / 7 cross-multiply
7[ 5x - 6 ] = 42 * 4
35x - 42 = 168 add 42 to both sides
35x = 210 divide both sides by 35
x = 6