Question

Se considera functia f:R->R,f(x)=2x+3.

Answer 1

Răspuns:

a) A de coord (a,3)

f(a) = 3 }

f(a) = 2a+3 } => 2a+3 =3 => 2a = 0 => a = 0 => A(0,3)

b) B de coord (-1,b)

f(-1) = b }

f(-1) = -1 × 2 + 3 } => b = -2 + 3 = 1 => B(-1,1)

c) C(c,c) (notam cu coord c si c deoarece acestea sunt egale)

f(c) = c }

f(c) = 2c+3} => c = 2c+3 <=> -c = 3 => c = -3 => C(-3,3)

d) D(d,2d)

f(d) = 2d

f(d) = 2d + 3

=> 2d = 2d + 3 (imposibil)