4x - 5y = -12
-x + 5y = 18
Add the equations together:
4x + -x = 3x
-5y + 5y = 0
-12 + 18 = 6
So now you have:
3x = 6
Divide both sides by 3:
X = 2
Now you have the value of x, replace x with 2 in one of the equations and solve for y:
4(2) -5y = -12
8 -5y = -12
Subtract 8 from both sides:
-5y = -20
Divide both sides by -5:
Y = 4
The solution is x = 2 and y = 4 which is written as (2,4)
Answer:24 cards - 20%= 19.2
Step-by-step explanation:
0.8 is 20% of 4. This is because 20% of something occurs when something is divided by 5, since it is 1/5 of 100. You multiply 0.8*5, and you get 4.
To complete the solution of - x - 8y = -1, we first need to substitute x for -15.
As so:
-(-15) - 8y = -1
15 - 8y = -1
Next, we can subtract 15 from each side to get:
15 - 15 - 8y = -1 - 15
- 8y = -16
Now, we can divide by -8 on each side to get the y by itself:
-8y / -8 = -16 / -8
y = -16 / -8
y = 2
There we go! <em>y</em> = 2 when x = -15! Hope I could help you out! Have a good one.