Math, asked by sanjay2727, 8 months ago


5. The first term of an A.P. is 5, the common difference is 3 and the last term is 80; find the
number of terms.​

Answers

Answered by 125ANUSHKA
2

The answer is attached

Please mark my answer as brainliest

Attachments:
Answered by Anonymous
3

Step-by-step explanation:

{  \sf{  \underline{  \red{  \underline{ \red{Given}}}} : -}}

 \displaystyle \sf \bigstar \:  \: 1st \: term \:  =  \: 5  \:  \:  \:  \:  \:  \: \\  \\  \displaystyle \sf \bigstar \: common \: diff \:  = 3 \\  \\  \displaystyle \sf \bigstar \: a(n) = 80 \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:

 \displaystyle \bigstar \:   \sf {\underline{using \: formula}}

 \displaystyle \longrightarrow \:   \boxed{ \underline{ \boxed{ \bold{a(n) = a +( n - 1)d}}}}

{  \sf{  \underline{  \red{  \underline{  \red{Solution}}}} : -}}

 \displaystyle \tt :  \implies \: a(n) = a + (n - 1)d \\  \\ \displaystyle \tt :  \implies \: 80 \:  = 5 + (n - 1)3 \:  \:  \\  \\ \displaystyle \tt :  \implies80 = 5 + 3n - 3 \:  \:  \:  \:  \:  \:  \:  \\  \\ \displaystyle \tt :  \implies80 - 2 = 3n \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \\  \\ \displaystyle \tt :  \implies78 = 3n \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \\  \\ \displaystyle \tt :  \implies  \: n \:  = 26 \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:

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