Since you need an isolated variable to use the substitution method, we need to re-arrange one of the equations. This will probably be easiest to do with the first one.
Add 5y to both sides of the first equation.
x=10+5y
Now, in the second equation, put in 10+5y in any spot that has an x.
2(10+5y)-10y=20
Distribute the 2 to both numbers in the parenthesis.
20+10y-10y=20
Combine like terms.
20=20
This means that the two equations are actually the same. You can see this if you multiply the whole first equation by 2
2(x-5y=10)
2x-10y=20, which is the same as the second equation. Therefore, the two equations are actually the same one.
Answer:
x = 3
Step-by-step explanation:
(4/5)^x = 64/125 means that 4^x / 5^x = 64/125
x can only be 3 because 4^3 = 64 and 5^3 = 125
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Answer:
a = 10
Step-by-step explanation:
From the solution given, x = a and y = -1
Substitute for x and y in either of the equations
y = -x + 9
-1 = -a + 9
a = 9 + 1 = 10
2/3x - 1/2y = 3 |multiply both sides by 6
4x - 3y = 18
1/2x + y = 5 |multiply both sides by 2
x + 2y = 10
Answer: 4x - 3y and x + 2y = 10.
Answer: 12 minutes
Step-by-step explanation: Since there are 2 people and 24 minutes total, you have to divide the total time by the amount of people. The equation will be 24=2x, so divide 24 by 2 and you get 12
