Ni : Zn: Cu = 7:2:9 =7x : 2x : 9x
7x+2x+9x = 3.8
18x=3.8
x=3.8/18=1.9/9≈0.21
Ni: 7x=7*0.21=1.47 ≈1.5 kg
Zn: 2x=2*0.21=0.42≈0.4 kg
Cu: 9x=9*0.21=1.89 ≈1.9 kg
Check 1.5+0.4+1.9 =3.8 True
Answer:
Option C.
Step-by-step explanation:
The given equations are


We need isolate one of the variables, such that it appears by itself on one side of the equation.
Isolating a variable in two equations is easiest when one of them has a coefficient 1.
In equation 1, coefficient of B is 1. So, we can easily isolate one of the variables.
The equation is

Subtract 3A from both sides.

Multiply both sides by -1.

Therefore, the correct option is C.
Answer:
$2,860
Step-by-step explanation:
2,500 * 3.8% = 90 in interest a year
so
90 * 4 = 360 in interest
add that to what she put in
2,860
Answer:
-0.851
Step-by-step explanation:
The highest number in a negative is the smallest
A represents it, since it’s on the negative side