inverse functions

completely from scratch (instructions) look at functions notes, https://www.youtube.com/watch?v=EdQYcAsu7wA&list=PLqxP5EuGxPncabt7LxLs_KYkM_4Yf02cF&index=18

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y = 3x +4

y - 4 = 3x

(y-4) / 3 = x

f^-1 (x) = (x-4)/3

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y = x^2 - 9

y - 9 = x^2

v(y-9) = x

g^-1 = V(x-9)

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  1. find the inverse

y = 2x + 4

y - 4 = 2x

(x-4) / 2 = y

f^-1 (x) = (x-4)/2

  1. sub in the 10

(10-4)/2

6/2

3

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  1. work out f^-1

y = (2x+5) / 3

3y = 2x+5

3y-5 = 2x

(3y-5)/2 =x

f^-1 (x) = (3x-5)/2

  1. sub in 7

= (3(7)-5)/2

= (21-5)/2

= 16/2

= 8