Question

Daca x+2y=17 si y-3z=4 , atunci calculati:
a) x+3y-3z=
b) 2x+5y-3z=
c) ( 3x+6y)+(2y-6z)=
d) (2x_4y) ori( x+4y-6z)=
Este urgent!

Answer 1

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=34+4=38
c) (3x+6y)+(2y-6z)=[3(x+2y)]+[2(y-3z)]=3*17+2*4=51+8=59
d) (2x+4y)*(x+4y-6z)=2(x+2y)*(x+2y+2y-6z)=2(x+2y)*[(x+2y)+2(y-3x)]=2*17*(17+2*4)=34*(17+8)=34*25=850