Answer:
Step-by-step explanation:
3x - 4y = 13 (1)
2x + y = 5 (2)
——————
3x - 4y = 13
4(2x + y = 5) (2) times 4
——————-
3x - 4y = 13
8x + 4y = 20
——————-
11x = 33
x = 33/11
x = 3
Plug x = 3 in (2):
2(3) + y = 5
6 + y = 5
y = 5-6
y = -1
Thus, x = 3 and y = -1
Answer: x=15
Step-by-step explanation:
Equation: 107=(9x-115)+(4x+27)
Step 1: 9x+4x-115+27=107
Step 2: 13x-115+27=107
Step 3: 13x-88=107
Step 4: 13x-88+88=107+88
Step 5: 13x=195
Step 6: 13x/13=195/13
x=15
120 seconds is 2 * 60s
60s is 1 minute, so 2*60s = 2 minutes
When you add them together you get 238.
If x represents the mass of 1 ball in kg, then the balance shows ...
... 6x = x + 9 kg
... 5x = 9 kg
Then 6x is ...
... (6/5)·5x = (6/5)·9 kg = 10.8 kg
0.8 kg = 0.8·1000 g = 800 g
so 10.8 kg is ...
... D. 10 kg 800 g