Answer:
B) 1, 2, 2, 1
Step-by-step explanation:
In given equation:
Left side: Right Side:
2 Na 1 Na
1 S 1 S
1 H 2 H
1 Cl 1 Cl
To equal the number of Na and H atoms on both sides, HCl and NaCl will have a coefficient of 2 to balance the equation while Na₂S and H₂S will have a coefficient of 1.
1 Na₂S + 2 HCl ⇒ 2 NaCl + 1 H₂S
Answer:
14. - 15
Step-by-step explanation:
The first one is located at 14. The second one is located at - 15
25x+20y=455
x+y=20
20x+20y=400
-25x-20y=-455
-5x=-55
x=11
11+y=20
y=9
Solved it as well, sorry if I wasn't supposed to
Answer:
(3)
Step-by-step explanation:
if Maria is 39 in 10 years and m is her age today then you would have to add 10 to m to get 39
m+10=39 years old
Let p be the prize of a pen and m the prize of a mechanical pencils. If you buy six pens and one mechanical pencil, you spend 6p+m. We know that this equals 9, because you get 1$ change from a 10$ bill.
Similarly, if you buy four pens and two mechanical pencils, you spend 4p+2m, which is 8$, because now you get a $2 change. Put these equation together in a system:

Now, if you multiply the first equation by 2, the system becomes

Subtract the second equation from the first:

Plug this value into the first equation to get
