问题
解答题
已知:a+b=4,ab=﹣2,求代数式(4a﹣3b﹣2ab)﹣(a﹣6b+ab)的值
答案
解:原式=4a﹣3b﹣2ab﹣a+6b﹣ab
=3a+3b﹣3ab
=3(a+b)﹣3ab
当a+b=4,ab=﹣2时,
3(a+b)﹣3ab
=3×4﹣3×(﹣2)
=18
已知:a+b=4,ab=﹣2,求代数式(4a﹣3b﹣2ab)﹣(a﹣6b+ab)的值
解:原式=4a﹣3b﹣2ab﹣a+6b﹣ab
=3a+3b﹣3ab
=3(a+b)﹣3ab
当a+b=4,ab=﹣2时,
3(a+b)﹣3ab
=3×4﹣3×(﹣2)
=18