The correct answer is (a). The solution is a=-5 and b=3. This is (-5,3) written as an ordered pair.
We want to get rid of one variable (a or b) and so we need to either add or subtract one equation from the other.
1) Subtract equation 2 (the bottom one) from equation 1.
The variable a is eliminated as a minus a leaves nothing. As seen above only one variable (b) remains.
2) Solve new equation to find b.
3) Replace b with 3 in either equations to find the value of a.
Therefore there is one solution : a=-5 and b=3. This can be written as (-5,3).
You can plug these values into the other equation to check if they are correct.