Question

(UNAMA) Dada a função f(x)=ax+b e sendo f(1)=3 e f(2)=9 o valor de f(0) será

Answer 1

a + b = 3(-1)
2a + b = 9

- a - b = - 3
2a + b = 9
    a = 6
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a + b = 3 ==> b = 3 - a ==> b = 3 - 6 ==> b = - 3
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Y = ax + b ==> y = 6x - 3