How do you solve #x − 5 = −10#?
x = -5
x - 5 = -10
Bringing the constants to one side, and the variable on the other; remember to change the signs as you shift
x = -10 + 5
x = -5
I have shown how to arrive at the answer from first principles so that you can use the shortcut with confidence.
This we know to be true
Suppose we subtracted 2 only from the left hand side (LHS)
To make this be correct we apply the golden rule:
so we subtract 2
End up with
The brackets are only there to show the original parts of the equation.
But +5-5=0 and 5-10 = -5 giving
The shortcut gets you to the same place but very much quicker.
With addition; to move something to the other side of the equals sign do so but change its sign.