Question

Is f={(1,0),(2,3),(3,6),(4,9)} a function ? If this

is described by the formula f(x)=ax+b .Find the

value of a and b.​

Answer 1

ANSWER

f={(1,1),(2,3),(0,−1),(−1,−3)}

f(x)=ax+b

(1,1)∈f

⇒f(1)=1

⇒a×1+b=1

⇒a+b=1 .....(1)

(0,−1)∈f

⇒f(0)=−1

⇒a×0+b=−1

⇒b=−1

On substituting b=−1 in eqn (1), we get

a+(−1)=1

⇒a=1+1=2

Thus the respective values of a and b are 2 and −1