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f (x ) = - 5 x + 3

f ( 3) = - 15 + 3 = - 12

f ( - 4 ) =  20 + 3 = 23

f ( 2) = - 10 + 3 = - 7

f ( - 7 ) = 35 + 3 = 38

- 5 x + 3 = 3

- 5 x = 3 - 3

- 5 x = 0

x = 0

- 5 x + 3 = - 7

- 5 x = - 7 - 3

- 5 x = - 10

x = 2