Solve the systems of equations using the substitution method
4x-3y=8
x=-31+9y

Which of these tables represents a non-linear function?

How many 3-digit numbers can you write using only digits 1 and 7? (of course, digits can repeat.) how many 3-digit numbers can you write using only digits 1 and 7? (of course, digits can repeat.)

How many and of which kind of roots does the equation f(x)=x3−x2−x+1