If there are no repeating x values and an x value only goes to <em>one</em><em> </em>y value, then yes, it is a function.
Set up the equation 3x+1= 4x-7 and you’ll get your answer
I think the relationship between the weight of a stack of standard 8.5x11 copier paper vs number of sheets of paper is proportional because :
Let us assume here, in this situation that each page has the same weight so if i want to find the weight of the complete stack, i will multiply the number of sheets of paper by the weight of a single sheet of paper.
y = x² - 4x + 4
0 = x² - 4x + 4
0 = x² - 2x - 2x + 4
0 = x(x) - x(2) - 2(x) - 2(-2)
0 = x(x - 2) - 2(x - 2)
0 = (x - 2)(x - 2)
0 = (x - 2)²
0 = x - 2
+ 2 + 2
2 = x
(x, y) = (2, 0)