54x+38y−3(4x−7y)=?
We begin by addressing the parenthesis:
Remember that:
When we multiply a positive number by a negative number, the result will be negative.
When we multiply a negative number by a negative number, the result will be positive.
Hence we obtain the following:
We then multiply and change the sign according to the rules:
Next we join together the x coefficients:
We also join together the y coefficients:
Finally we obtain: