Question

Isolating a variable in two equations is easiest when one of them has a coefficient 1.

Answer 1

Answer:

Option C.

Step-by-step explanation:

The given equations are

$3A-B=5$

$2A+3B=-4$

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

$3A-B=5$

Subtract 3A from both sides.

$-B=5-3A$

Multiply both sides by -1.

$B=3A-5$

Therefore, the correct option is C.