Ok so for starters you want to choose an equation and solve for a variable.
So, I am going to choose x from the first equation.
Add y to both sides and you get x=11+y
Next, substitute 11+y for x in the other equation so you get...
2(11+y) +10y=-6
Next distribute the 2 throug the 11 and the y
22+2y+10y=-6
12y=-28
y=-28/12
reduce this fraction to make this easier.
y=-7/3
Now plug in why to either of the equations to find x
x-(-7/3)=11
x+7/3=11
x=11-(7/3)
x=(33/3)-(7/3)
x=26/3
so x = 26/3 and y = -7/3
you can also check to see if this is correct by substituting each of these values into the equations.
So is 4 floors / 10 seconds
If you have 60 seconds you can multiple 10 by 6 because 10×6=60
so you also have to multiple 4 by 6
4×6=24
and because it's descending it's 100-24= 76
Answer:
14.99 hours
Step-by-step explanation:
The formula for half-life is given as,
R/R' = 2ᵃ/ᵇ...................... Equation 1
Where R= Original mass of sodium-24, R' = mass of Sodium-24 after disintegration, a = Total time taken for sodium-24 to disintegrate, b = half-life of sodiun-24.
Given: R = 1 kg, R' = 0.0156 kg, a = 90 hours
Substitute into equation 1 and solve for b
1/(0.0156) = 2⁹⁰/ᵇ
Taking the log of both side
log[1/(0.0156)] = log(2⁹⁰/ᵇ)
log[1/(0.0156)] = 90/b(log2)
90/b = log[1/(0.0156)]/log2
90/b = 6.0023
b = 90/6.0023
b = 14.99 hours
b = 14.99 hours.
Hence the half-life of Sodium-24 is 14.99 hours
This is an addition problem.
Rearrange the given equations as
<span>+ f(x)=5x-2
+g(x)=2x+1
----------------
Add up each column, as follows: (f+g)(x) = 7x - 1 (answer)</span>
