Question

1) Dada a função polinomial do 1º grau , f (x) = 2x+1 , Determine:
a) f (-1)
b) f (0)
c) f (1)
d) f (3)
2) Dada a função função f (x) = ax+b , com ≠0 , sendo f (1) = 3
f (2) = 5 , calcule f (x)
3) Construa o gráfico das funções:
a) f (x) = ¹/²
b) f (x) = -2
c) f (x) = 3

Answer 1

$a)f(-1)=2(-1)+1=-2+1=\boxed{-1}$

$b) f(0)=2.0+1=\boxed{1}$

$c) f(1)=2(1)+1=\boxed{3}$

$d) f(3)=2.3+1=\boxed{7}$

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$2) f(x)=ax+b\\f(1)=3\\a(1)+b=3\\a+b=3\\f(2)=5\\a(2)+b=5\\2a+b=5\\ \left \{ {{a+b=3} \atop {2a+b=5}} \right. \\\\a-2a+b-b=3-5\\-a=-2\\a=2\\a+b=3\\2+b=3\\b=1\\f(x)=ax+b\\\boxed{f(x)=2x+1}$

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Acredito que a ultima é da seguinte maneira :

$a) f(x)=\frac{1}{2}\\f(x)=y\\y=2x+1\\\frac{1}{2}=2x+1\\x=\frac{-1}{4}\\P(\frac{-1}{4},\frac{1}{2})$

$b)f(x)=-2\\-2=2x+1\\2x=-3\\x=\frac{-3}{2}\\\\P(\frac{-3}{2},-2)$

$c)f(x)=3\\3=2x+1\\2x=3-1\\2x=2\\x=1\\\\P(1,3)$

Apenas ligue todos esses pontos agora no gráfico .