To solve the equation P - Q = -R for Q, we need to isolate the variable Q on one side of the equation.
First, let's get rid of the negative sign in front of R by multiplying both sides of the equation by -1:
(-1)(P - Q) = (-1)(-R)
This gives us:
-Q + P = R
Now, we want to isolate Q, so we move P to the other side of the equation:
-Q = R - P
Finally, to solve for Q, we can multiply both sides of the equation by -1:
(-1)(-Q) = (-1)(R - P)
Which simplifies to:
Q = -R + P
Therefore, the solution for Q in the equation P - Q = -R is Q = -R + P.