Blake is working his way through school. he works two part time jobs for a total of 31 hours a week. job pays $5.80 per hour and job b pays $7.50 per hour. how many hours did he work at each job the week that he made $212.10 use variables x and y to set up two equations to solve the given problem

Really need on these. i have no idea what to do

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

65 8 7 4 5 6 8 4 3 2 1 9 5 6 4 2 1 6 5 1 5 1 3 2 3 5 multiply the third number in the first row by the seventh number in the third row. add this result to the fifth number in the second row. add to this total ten times the fourth number in the third row. subtract the eighth number in the first row from the result.