If a + b + c = -3 x + y = -9, -2c - 2a - 3y - 2b -3x?

Question

Given some information about several unknown variables, evaluate an expression containing those variables.

 

Answer 1

Given a +b + c = -3x+y =-9

Compute -2c-2a-3y-2b-3x = ?

 

Rearrange terms of above algebraic expression to -2a-2b-2c-3x-3y= ?

 

factor terms to -2(a+b+c)-3x-3y=?  Eq (1)

 

but a+b+c = -9, Substitute into above -2(-9)-3x-3y, 18-3x-3y=0

 

Now find x and y from the two equations 3x+3y=18, and -3x+y=-9

 

add equation terms to get 4y=9, y =9/4

 

Substitute -3x+y=-9, -3x+(9/4)=-9, -3x=-9-(9/4)=-45/4 and

x= -45/-12, x= 45/12 or 15/4, Now substitute in the Eq (1) above

 

-2(a+b+c)-3x-3y=?  , -2(-9)-3(15/4)-3(9/4)= 18-(45/4)-(27/4)=

 

18-(72/4)= 18-18=0