Answer: ab =6
have:
=> a + b + 1 = ab
⇔ a + b + 1 - ab = 0
⇔ b - 1 - a(b - 1) + 2 = 0
⇔ (b - 1)(1 - a) = -2
because a and b are postive integers => (b - 1) and (1 - a) also are integers
=> (b - 1) ∈ {-1; 1; 2; -2;}
(1 -a) ∈ {-1; 1; 2; -2;}
because (b -1).(1-a) = -2 => we have the table:
b - 1 -1 1 2 -2
1 - a 2 -2 -1 1
a -1 3 2 0
b 0 2 3 -1
a.b 0 6 6 0
because a and b are postive integers
=> (a;b) = (3;2) or (a;b) = (2;3)
=> ab = 6
Step-by-step explanation:
Answer: the rate uphill is 6 mph.
The rate downhill is 10 mph
Step-by-step explanation:
Let x represent the rate at which the jogger ran uphill.
The jogger runs 4 miles per hour faster downhill than uphill. This means that speed at which the jogger ran downhill is (x + 4) mph
Time = distance/speed
if the jogger can runs 5 miles downhill, then the time taken to run downhill is
5/(x + 4)
At the same time, the jogger runs 3 miles uphill. It means that the time taken to run uphill is
3/x
Since the time is the same, it means that
5/(x + 4) = 3/x
Cross multiplying, it becomes
5 × x = 3(x + 4)
5x = 3x + 12
5x - 3x = 12
2x = 12
x = 12/2
x = 6
The rate downhill is 6 + 4 = 10 mph
Answer:
y = 42
Step-by-step explanation:
18 - y = -24
18 + 24 - y = 0
18 + 24 = y
18 + 24 = 42
i think
Answer:
5x + y = -48
Step-by-step explanation:
(y + 3)/(x + 9) =m
=> y + 3 = -5x -45
=> 5x + y + 48 = 0
Add the 3 item totals, then divide that number by 100, then, take that number and multiply by 9 (this gets the tax total). then you are going to want to add the total of the 3 items, and the tax amount, and you have your answer. do this with all the peoples items :)
