Question

已知：x=y+3,求代数式四分之一（x-y）的平方-十分之三（x-y）+四分之三（x-y）的平方

Answer 1

x=y+3

x-y=3

1/4(x-y)²-3/10(x-y)+3/4(x-y)²+13/10(x-y)

=(x-y)²+(x-y)

=3²+3

=9+3

=12