Simple algebra questions?

Hi,

A = 3x + 5y + z

B = 8x - 3y - 5z

i A+B = 3x + 5y + z + 8x - 3y - 5z = 11x + 2y - 4z <==ANSWER

ii A-B = 3x + 5y + z - (8x - 3y - 5z) = 3x + 5y + z - 8x + 3y + 5z = -5x + 8y + 6z <==ANSWER

I hope that helps!! :-)

Is the first one "A= 3x + 5y + z"? That would make more sense.

Since it tells us that 8x - 3y - 5z is the same thing as B, instead of saying B, we can say 8x - 3y - 5z. We can do the same thing by using 3x + 5y + z instead of A. If we replace A and B in i with the x-y-z variables, we get the following:

(2x + 5y + z) + (8x - 3y - 5z). Adding variables to variables like them (2x + x = 3x or 5y + 9y = 14y), we get the following:

10x + 2y - 4z for i.

You can replace (or substitute) A with 2x+5y+z and B with 8x-3y-5 in ii, as well. The thing with substituting for B, there is a minus sign. So, you need to remember to use it for the entire equation:

-B = -(8x-3y-5) = -8x + 3y + 5

A= 3x + 5y + z and B = 8x - 3y - 5z

A+B = 3x + 5y + z + 8x - 3y - 5z = ...simplify

A-B = 3x + 5y + z -( 8x - 3y - 5z) = ...simplify

a+3x+5y+b=8x-3y-5z

a+b=8x-3y-5z-3x-5y=5x-8y-5z

a+3x+5y+b=8x-3y-5z

b=8x-3y-5z-3x-5y-a=5x-8y-5z-a

a-b=8x-3y-5z-5x+8y+5z+a=3x+5y+a

Is that a typo? I think you mean "Given that A =" instead of "Given that A +", correct?