b) if x = 2 and y = -1\n2y - 3x =

Explanation:

Step1: Substitute values of x and y

Substitute $x = 2$ and $y=-1$ into $2y - 3x$. So we get $2\times(-1)-3\times2$.

Step2: Calculate multiplications first

$2\times(-1)=-2$ and $3\times2 = 6$. The expression becomes $-2-6$.

Step3: Calculate the subtraction

$-2-6=-8$.

Answer:

$-8$