60×3.5²-120×3.5×1.5+60×1.5²
=60×(3.5²-2×3.5×1.5+1.5²)
=60×(3.5-1.5)²
=60×2²
=60×4
=240
啥是“”?
除去后面的“²”,前面可以简化为:
60x3.5x(3.5-2x1.5)+ 60x1.5
=60x(2+1.5)x0.5 +60x1.5
=60+60x1.5x1.5
=60+135
=195
60×3.5²-120×3.5×1.5+60×1.5²
= 60×3.5²-60×2×3.5×1.5+60×1.5²
=60×(3.5²-2×3.5×1.5+1.5² )
=60 ×(3.5-1.5)²
=60 ×4
=240
弟弟能把题目先写对吗
我看着挺着急的
60×3.5²-120×3.5×1.5+60×1.5²
=60×(3.5²-2×3.5×1.5+1.5²)
=60×(3.5-1.5)²
=60×2²
=240