How do I use substitution to solve the system? Please help Addition and equal key is not working
-5x plus 2y equal 16
y equal 2x plus 7
-5x+2y=16
y = 2x+7
Tika,
Doesn't the 2nd equation tell you what the value of y is ??
Just replace the y in the 2y of the first equation with the value of y in the second.
Give it a try, it is really easy.
Let me know what you got.
first equation:
-5x + 2y = 16
subbing in y = 2x+7
----> -5x + 2(2x+7) = 16
-5x + 4x + 14 = 16
-x = 2
x = -2
now put that back into
y = 2x+7
= 2(-2) + 7 = 3
all done
curious, at what grade level are you taking this?
Your question seems a bit sarcastic, but thank you for showing me step by step on how you got the answer. This is college level algebra, and I have always had trouble with algebra. I haven't taken a math course in over 16 years.
Was not meant to be scarcastic, simply trying to figure out the best way to explain it, there are several ways.
The question is asking x equals and y equals
To solve the system of equations using the substitution method, follow these steps:
1. First, write down both equations:
-5x + 2y = 16
y = 2x + 7
2. Solve one of the equations for one variable in terms of the other. In this case, we can solve the second equation for y:
y = 2x + 7
3. Now, substitute the expression for y in the first equation:
-5x + 2(2x + 7) = 16
4. Simplify the equation:
-5x + 4x + 14 = 16
-x + 14 = 16
5. Subtract 14 from both sides to isolate the variable:
-x = 2
6. Finally, divide by -1 to solve for x:
x = -2
7. Substitute the value of x back into one of the original equations to solve for y. Using the second equation since it's already solved for y:
y = 2(-2) + 7
y = -4 + 7
y = 3
So, the solution to the system of equations is x = -2 and y = 3.