Let x= months
So 50x is the total amount he pays after x months. You went to add 100 to this because there's a fixed cost of 100 for the phone
So you have the expression 100+50x which is the amount he pays after x months
Since he has a limit of 300,
100+50x < 300
Factor
x(2x-1)=0
x = 1/2, 0
Let :
T = Theresa age
H = her brother
We know :
T = H - 14
T + H = 35
Substitute T
H -14 + H = 35
2H - 14 = 35
2H = 49
H = 49/2 = 24.5
Since we know H = 24.5 we then can substitute it to either equation.
T = H - 14
T = 24.5 - 14
T = 10.5
Theresa is 10.5 years old
Her brother is 24.5 years old
Answer:
y = 4/3
Step-by-step explanation:
The two equations can be added to eliminate x:
(0.1x +0.5y) + (-0.1x -0.2y) + (1.2) +(-0.8)
0.3y = 0.4 . . . . . simplify
Divide by the coefficient of y to find y:
y = 0.4/0.3
y = 4/3
