Question

Daca x+y=2,5 si y+Z=6,4.Calculati
a) 3x+4y+z b)3x+6y+3z. c)5x+7y+2z

Answer 1

x + y = 2,5
y + z = 6,4
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a)  3x+4y+z = 3x+3y+y+z = 3(x+y) + (y+z) = 3×2,5 + 6,4 = 7,5 + 6,4 = 13,9

b)  3x+6y+3z = 3x+3y+3y+3z = 3(x+y)+3(y+z)=3×2,5+3×6,4=7,5+19,2=26,7

c) 5x+7y+2z = 5x+5y+2y+2z = 5(x+y)+2(y+z)=5×2,5+2×6,4=12,5+12,8=25,3