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The second term of an AP IS (x-y)and the fifth term is (x+y)then it's first term is? |
We know that the nth term of an A.P. is given by an=a+(n-1)d, where a is the first term and d is the common difference given, a2 = x-y ? a+(2-1)d = x-y ? a+d = x-y -----(1) also, a5 = x+y ? a+(5-1)d = x+y ? a+4d = x+y---------(2) (2)-(1) gives 3d = 2y d = 2y/3 substituting the value of d in (1) a+2y/3 = x-y a = x-y-2y/3 a = 3x-3y-2y/3 i.e., a = 3x-5y/3 |