Pls help! will give brainlist!

what is the Y coordinate of the ordered pair that satisfies the system of linear equations?

A. -2
B. 1
C. -1
D. 2

Find the length of the normal and the angle it makes with the positive x-axis. (see pictured below)

At noon a tank contained 10cm water. after several hours it contained 7cm of water. what is the percent decrease of water in the tank?

An unknown number x is at most 10. which graph best represents all the values of x? number line graph with closed circle on 10 and shading to the right. number line graph with open circle on 10 and shading to the right. number line graph with open circle on 10 and shading to the left. number line graph with closed circle on 10 and shading to the left.