Put 7x-5y+20 into slope intercept form

For the equations below which statement is true ?

Offering 30 if a plus b plus c equals 68 and ab plus bc plus ca equals 1121, where a, b, and c are all prime numbers, find the value of abc. the answer is 1978 but i need an explanation on how to get that.

Last one and the bottom answer choice is y=(x-4)^2+1 you guys!