Is the function represented by the table non-linear?

Nope!

Step-by-step explanation:

It's linear, because it has a continuous pattern. Look!

x values: 6, 7, 8, 9

y values: 4, 2, 0, -2

X values: We add 1 each time

Y values: We subtract 2 each time

I hope it helps!

in problems involving proportions, we can use cross products to test whether two ratios are equal and form a proportion. to find the cross products of a proportion, we multiply the outer terms, called the extremes, and the middle terms, called the means.

hope it