1.2345^2+(0.7655)^2+2.469×0.7655-2.5^2

问题描述:

1.2345^2+(0.7655)^2+2.469×0.7655-2.5^2

=1.2345²+2×1.2345×0.7655+0.7655²-2.5²
=(1.2345+0.7655)²-6.25
=4-6.25
=-2.25