Answer:
we need to see the problem your reffering to, to be able to help you
Step-by-step explanation:
2x+4y=0
3x+y=10
So what we want to do is get y onto one side by itself using whatever equation you like.
So I'm taking 2x+4y=0 and subtracting 4y from both sides
So we end up with
2x=4y
Divide both sides by four
2/4x is 1/2 x
So we get 1/2x=y
Take this and plug it into the other equation
3x+y=10
3x+1/2x=10
Add your like terms
3 1/2x=10
Putting 3 1/2 as a mixed number we get 7/2
So..
7/2x=10
Multiply by the opposite of 7/2 on both sides
Which is 2/7 this will cancel out the left side.
So we end up with
X= 10•2/7
X=20/7
Which is 2 and 6/7 as a mixed number.
Exponential decay is a very common process especially when we are talking about radioactive materials. So, there is already a common formula for this type of behavior which is written below:
A = Pe^-rt
where
A is the amount left after time t
P is the initial amount at t=0
r is the rate
Substituting the values,
A = (780 g)(e^-0.163*16)
A = 57.5 g
X equals 7.1 if you round to the nearest tenth
Hello from MrBillDoesMath
Answer: 12, 9
Discussion:
Let x be the first number and y the second number. The form the problem statement:
x + y = 21
x - y = 3
Add the two equations. This gives:
(x + x ) + ( y-y) = 21 + 3 =>
2x + 0 = 24 =>
x = 12
Since x -y =3, substituting in the value of x gives, 12 - y = 3 so y = 9
Thank you,
Mr. B
