Answer:
Step-by-step explanation:
1) 2x -y = 1 -------1
3x - y = -6 ------2
Subtract eqn 2 from eqn 1
-x = 1--6 = 7
x = -7
Put x= -7 in eqn 1
2*-7-y = 1
-14-y = 1
- y = 15
y = -15
2) 4x +2y = 10------1
y = 4x + 2--------2
Put eqn 2 in eqn 1
4x + 2 ( 4x+ 2) = 10
4x + 8x + 4 = 10
12x = 6
x = 6/12 = 1/2
Put x = 1/2 in eqn 2
y = 4* 1/2 + 2= 2 + 2
= 4
3) 6x - y = 2------1
y = 3x + 4---------2
Put eqn 2 in eqn 1
6x - (3x +4) = 2
6x - 3x - 4 = 2
3x = 6
x = 2
y = 3*2 + 4 = 6 + 4
= 10
Answer: She started with $160.
It will take 6 weeks before she has less than half of what she originally invested.
Step-by-step explanation:
If her money is decreasing in value by 11% each week, it means that the rate at which it is decreasing is exponential.
We would apply the formula for exponential decay which is expressed as
A = P(1 - r)^t
Where
A represents the value of the investment after t weeks.
t represents the number of weeks.
P represents the initial value of the investment.
r represents rate of depreciation.
From the information given,
A = $142.40
r = 11% = 11/100 = 0.11
t = 1
Therefore
142.40 = P(1 - 0.11)^1
142.40 = P(0.89)
P = 142.4/0.89
P = 160
For her to have half of what she invested originally, then
80 = 160(0.89)^t
80/160 = (0.89)^t
0.5 = (0.89)^t
Taking log of both sides to base 10
Log 0.5 = log0.89^t = tlog0.89
- 0.3010 = - 0.051t
t = - 0.3010/- 0.051
t = 5.9
Approximately 6 weeks
Answer:
x = 9 m
y = 1 m
Step-by-step explanation:
6/1 = x/1.5
x = 1.5 × 6
x = 9
6/1 = 6/y
6y = 6
y = 1
Answer:
7,515
Step-by-step explanation:
Answer:
Tenacious tennis: y=5x+120
Totally Tennis: 8x
Toys r us: y=20x
Lego club: y=17x+36
Step-by-step explanation:
y=cost x= tennis court usage charge
Tenacious tennis: y=5x+120
Totally Tennis: 8x
8.)
y=cost x=lego set
Toys r us: y=20x
Lego club: y=17x+36
