Question

What is its inverse? F= {5,-1),(4,8),(6,8),(4,9)

Answer 1

Explanation:

m(gradient) =y2-y1/x2-x1

=8-(-1) /4-5

=8+1/-1

=9/-1

=-9

y-y1=m(x-x1)

y-(-1)=-9(x-5)

y+1=-9x+45

y=9x+45-1

y=9x+44(rule)

Inverse>y+44=9x

y+44/9=9x/9

x=y+44/9

Therefore inverse is y=x+44/9

Answer 2

Hence, f −1 (x) = x/3 + 2/3 is the correct answer.

Explanation:

Verify (f ∘ f−1) (x) = x

(f ∘ f−1) (x) = f [f −1 (x)]

= f (x/3 + 2/3)

⟹ 3(x/3 + 2/3) – 2

⟹ x + 2 – 2

= x

Hence, f −1 (x) = x/3 + 2/3 is the correct answer.