Alright, if it tells you to solve by substitution, you need to solve for either one of the variables (either x or y) in one of the equations. Let's say you solved for x. Then with the value of one of the variables (it will be an expression with y), you substitute it into the other equation in which you will get a value without variables as y. Now substitute that value y back into the first equation in which you solved for x to get the value of x.
So for 1) 5x + y = 0 y = -5x
Now plug -5x as y into the other equation -5x + y = -10 -5x -5x = -10 -10x = -10 x = 1
Now with x=1, plug that back into y=-5x. y = -5(1) y = -5
The rate per hour is equal to the total bagels made divided by the time to make them. 360 ÷ 10 = 36 If for 1 hour they make 36 bagels, for 13 hours they can bake 36 x 13 = 468 bagels.
