己知有理数a的相反数是53,有理数b的倒数是-52,则3a+5b3a-5b的值是______.-数学

题目简介

己知有理数a的相反数是53,有理数b的倒数是-52,则3a+5b3a-5b的值是______.-数学

题目详情

己知有理数a的相反数是
5
3
,有理数b的倒数是-
5
2
,则
3a+5b
3a-5b
的值是______.
题型:填空题难度:中档来源:不详

答案

∵有理数a的相反数是class="stub"5
3
,有理数b的倒数是-class="stub"5
2

∴a=-class="stub"5
3
,b=-class="stub"2
5

class="stub"3a+5b
3a-5b
=
3×(-class="stub"5
3
)+5×(-class="stub"2
5
)
3×(-class="stub"5
3
)-5×(-class="stub"2
5
)
=class="stub"-5-2
-5+2
=class="stub"7
3

故答案为:class="stub"7
3

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