Question

Daca x+2y=17 si y-3z=4,calculati:
a)x+3y-3z=
b)2x+5y-3z=
c)(3x+6y)+(2y-6z)=
d)(2x+4y)•(x+4y-6z)=​

Answer 1

Răspuns:

x + 2y = 17

y - 3z = 4

a) x + 3y - 3z = x + 2y + y - 3z =

  = (x + 2y) + (y - 3z) = 17 + 4 = 21

b) 2x + 5y - 3z = 2x + 4y + y - 3z =

  = 2 · (x + 2y) + (y - 3z) = 2 · 17 + 4 = 38

c) (3x + 6y) + (2y - 6z) = 3 · (x + 2y) + 2 · (y - 3z) = 3 · 17 + 2 · 4 = 59

d) (2x + 4y) · (x + 4y - 6z) =​ 2 · (x + 2y) · (x + 2y + 2y - 6z) =

   = 2 · (x + 2y) · [(x + 2y) + 2 · (y - 3z)] =

   = 2 · 17 · (17 + 2 · 4) = 2 · 17 · 25 = 850

Explicație pas cu pas: