Use the substitution method:
2x - 6y = -12
x - 2y = -8
Then x = 2y - 8
Substitute in the first equation:
2(2y - 8) - 6y = -12
4y - 16 - 6y = -12
-2y = 4
y = -2
Now substitute y in one of the two equations given you prefer:
For example x-2*(-2) = -8
x + 4 = -8
x = -12
The solutions are x = -12 and y = -2
1/4 per hamburger, 4 hamburgers=1 pound 20/4= B. 5 pounds
We know that
<span>This problem can be represented through the following equation
</span>
A = A₀(1/2)^t/h
where
A-----------> is the amount of substance left after time t
A₀ ----------> is the original amount---------> 2 g
h-------------> is the half-life-----------> 8 days
for A=0.04 g
t=?
0.04 = 2(1/2)^t/8
0.02 = (1/2)^t/8
Take ln on both sides:
ln(0.02) = ln [(1/2)^t/8]
ln(0.02) = (t/8)(ln 1/2)
t = 8*ln(0.02)/ln(1/2)
t = 45.15 days
the answer is 45.15 days
Answer:
30 km/h
Step-by-step explanation:
usual speed= x km/h
increased speed= x +10 km/h
distance= 360 km
time difference= 3 h
- 360/x= 360/(x+10) +3
- 360/x= (360+ 3x+30)/(x+10)
- 360(x+10)= x(390+3x)
- 360x+3600= 390x+ 3x²
- 3x² + 30 x -3600=0
- x²+10x-1200=0
- x=30 km/h
