设数列{an}和{bn}都是等差数列,且a1=25,b1=75,a2+b2=100.设CN=AN+BN,则C10=?

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设数列{an}和{bn}都是等差数列,且a1=25,b1=75,a2+b2=100.设CN=AN+BN,则C10=?
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设数列{an}和{bn}都是等差数列,且a1=25,b1=75,a2+b2=100.设CN=AN+BN,则C10=?
设数列{an}和{bn}都是等差数列,且a1=25,b1=75,a2+b2=100.设CN=AN+BN,则C10=?

设数列{an}和{bn}都是等差数列,且a1=25,b1=75,a2+b2=100.设CN=AN+BN,则C10=?
a2=a1+d
b2=b1+r
因为a2+b2=100,所以a1+d+b1+r=100
又因为a1=25,b1=75,所以d+r=0
c10=a10+b10=a1+9d+b1+9r=25+75+9*0=100

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