Question

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Answer 1

Răspuns:

f:R→R ; f(x) = $\frac{12-4x}{3}$

a) f(1) = $\frac{12-4}{3} = \frac{8}{3}$

f(2) = $\frac{12-8}{3}= \frac{4}{3}$

f(3) = $\frac{12-12}{3}=0$

f(4) = $\frac{12-16}{3}=-\frac{4}{3}$

⇒ f(1)·f(2)·f(3)·f(4) = 0

b) Gf ∩ Ox = {A}

Gf ∩ Ox ⇒ f(x) = 0 ⇒ $\frac{12-4x}{3}$ = 0 ⇒ x = 3 ⇒ A(3,0)

Gf ∩ Oy = {B}

Gf ∩ Oy ⇒ f(0) = y = $\frac{12}{3}$ = 4 ⇒ B(0,4)

AB = $\sqrt{(Xa-Xb)^{2}+(Ya-Yb)^{2} } = \sqrt{(3-0)^{2}+(0-4)^{2} } = \sqrt{25 } = 5$