1,2n-0.8n+8n,当n=0.5时,求值2,5a-7b+3a+2b,当a=1.5,b=0.25时,求值
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1,2n-0.8n+8n,当n=0.5时,求值2,5a-7b+3a+2b,当a=1.5,b=0.25时,求值
1,2n-0.8n+8n,当n=0.5时,求值
2,5a-7b+3a+2b,当a=1.5,b=0.25时,求值
1,2n-0.8n+8n,当n=0.5时,求值2,5a-7b+3a+2b,当a=1.5,b=0.25时,求值
1、 2n-0.8n+8n
=1.2n+8n
=9.2n
当n=0.5时
9.2n
=9.2×0.5
=4.6
2、5a-7b+3a+2b
=5a+3a-7b+2b
=(5a+3a)-(7b-2b)
=8a-5b
当a=1.5,b=0.25时
8a-5b
=8×1.5-5×0.25
=12-1.12
=10.75
1.1-0.4+4=4.6
2.8a-5b=12-1.25=10.75
致绍伏
1 2n-0.8n+8n=(2-0.8+8)n=9.2n 当n=0.5时 9.2n=9.2×0.5=4.6
2 5a-7b+3a+2b=(5+3)a+(2-7)b=8a-5b 当a=1.5 b=0.25时 8a-5b =10.75
1.2n-0.8n+8n
=10n-0.8n
=9.2n
当n=0.5时
9.2n=9.2×0.5 =4.6
2.5a-7b+3a+2b
=5a+3a-7b+2b
=8a-5b
当a=1.5,b=0.25时
8a-5b=8×1.5-5×0.25
=12-1.12
=10.75
1,2n-0.8n+8n=9.2n=9.2×0.5=4.6
2,5a-7b+3a+2b=8a-5b=8×1.5-5×0.25=10.75