用遞等式計算【能簡算的要簡算】. 8.6÷4-8.6÷2 = = = HELP!

用遞等式計算【能簡算的要簡算】. 8.6÷4-8.6÷2 = = = HELP!

=8.6*1/4-8.6*1/2
=8.6*(1/4-1/2)
=8.6*(-1/4)
=-2.15