What did you label as the halfway mark? Why?

500 ml

Step-by-step explanation:

because there are 10 marks and the distance between the bottom of the beaker is the same distance as the distance between each mark. That makes the distance between each mark the same (100 ml) and the half way mark is 5. so 100 x 5 is 500

step-by-step explanation:

step 1: solve one of the equations for one of the variables. let's solve the first equation for y:

step 2: substitute that equation into the other equation, and solve for x.

step 3: substitute x = 4 x = 4 x=4 into one of the original equations, and solve for y.