For one of my math assignments I have to find out which solution is, One solution
Infinite solution
and No solution
what i've got for it is

y=x+6 and 3x-3y=-18 (Infantaly amount of solutions)
y=-4x+11 and -6+y=11 (One solution)
y=-2x+5 and 2x+y=-7(no solution)

Is this correct?

Find the greatest common factor of the polynomial: 10x^5+15x^4-25x^3 10x^5 x^3 5x^3 5

Elena and her husband marc both drive to work. elena's car has a current mileage (total distance driven) of 15,000 and she drives 23,000 miles more each year. marc's car has a current mileage of 46,000 and he drives 9,000 miles more each year. will the mileages for the two cars ever be equal? explain.

Peter applied to an accounting firm and a consulting firm. he knows that 30% of similarly qualified applicants receive job offers from the accounting firm, while only 20% of similarly qualified applicants receive job offers from the consulting firm. assume that receiving an offer from one firm is independent of receiving an offer from the other. what is the probability that both firms offer peter a job?