3x + 5 = 23
5 more than(addition) 3 times(multiplication) a variable(x) is(equals) 23
(you add 5 to 3x)
If you need to solve for "x", you need to isolate/get the variable "x" by itself in the equation:
3x + 5 = 23 Subtract 5 on both sides
3x + 5 - 5 = 23 - 5
3x = 18 Divide 3 on both sides to get "x" by itself

x = 6
I'm not exactly sure what you're asking but in total there's 800 kids at East Side Elementary School.
Find the slope:
(-19 - 11) / (-8 - 2) = (-30/-10) = 3
Find the y intercept:
y = mx + b
11 = 3(2) + b
b= 5
So equation is:
y = 3x + 5
Let's calculate for the tablespoons of sugar to tablespoons of milk ratio for Mark, Sharri and Eve.
Mark: 3/2 = 1.5
Sharri: 4/3 = 1.3
Eve: 9/6 = 1.5
From the solution, Eve has an equivalent ratio to that of Mark's.
15-4 = 11
11 x 2 = 22
22 + 2/3 = 68/3