Question

Ashur solves the following system of linear equations.

Answer 1

The given equations that make up the systems are:

-3a+7b=-16...................(Equation 1)

-9a+5b=16...................(Equation 2)

To find the values of a and b we will have to solve the two equations. To solve the equations let us employ the method of elimination.

Let us multiply (Equation 1) by -3. This will give us:

$-3\times (-3a+7b=-16)=9a-21b=48$...........(Equation 3)

Let us now add (Equation 2) to (Equation 3) to eliminate a. This will give us:

-16b=64

$\therefore b=-4$

Plugging this value of b in any of the equations we will get the value of a. Let us plug it in (Equation 1). This gives:

$-3(-4)+7b=-16$

$12+7b=-16$

$\therefore b=\frac{-28}{7}=-4$

Thus, out of the given options, the first option is the correct one. The values of a and b are both equal to –4.

Answer 2

A. first choice

The values of a and b are both equal to –4.