Solve the system of linear equations by substitution. y = 4x
x +y = -15
The solution of the system is

(-3, -12)  

Step-by-step explanation (work shown in attached picture):

1) First, since y is already isolated in the first equation, substitute that value of y into the other equation. So, substitute 4x for the y in x + y = -15 and solve for x. We find that x = -3.

2) Then, substitute that value for x back into any one of the equations. I chose to do it with the first equation. Substitute -3 for x in y = 4x, then solve for y this time. This gives us y = -12.

Since x = -3 and y = -12, the solution is (-3, -12).

a function could be identified in 3 ways either on a chart,graph, or ordered pairs. first a function is that each point has its own. the rule is that there can be many x's to one y but there can not be 2 x's at different y's. so on a graph when you put a straight line through the y's there should be one dot only to be a function.

step-by-step explanation:

47 - 90 = 43

43 - 180 = x

x = 137