Question

15^2-4*2.5^2利用因式分解计算

Answer 1

15^2-4*2.5^2

=15^2-(2*2.5)^2

=15^2-5^2

=(15+5)(15-5)

=20*10

=200

204^2+54^2-204*108

=204^2-2*54*204+54^2

=(204-54)^2

=150^2

=22500