How do you solve 9c(c-11)+10(5c-3)=3c(c+5)+c(6c-3)-3 0 if we are multiplying polynomials by monomials

Julius sold five times as many computers as sam sold last year. in total, they sold 78 computers. how many computers did julius sell?

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Florence price's brownies and more sells all types of cookies and pastries. on tuesdays, they markdown all brownies 75% to a sale of $1.50 a dozen. find the selling price and the markdown of a dozen brownies.