当a=4,b=5时,求2(a+b)+3a-b
问题描述:
当a=4,b=5时,求2(a+b)+3a-b
请化简求职
答
解
2(a+b)+3a-b
=(2a+3a)+(2b-b)
=5a+b
=5×4+5
=25为什么依次算下来不对啊,,,你算一下代入算吗,还是
2(a+b)+3a-b
=2×(4+5)+3×4-5
=2×9+12-5
=18+12-5
=30-5
=25给你看依次计算,,,,
2(a+b)+3a-b
=2*(4.2+5)+3*4.2-5
=2*9.2+12.6-5
=18.4+12.6-5
=31-5
=26你上面a是4啊,你弄错了,还是打错了亲,,,对不起啦,,,打错了哈,,,我会做了,,,谢谢哈嗯嗯,记得采纳了