# need help simplifying these please

#### tbatam

Joined Nov 30, 2013
1
11. Simplify the following Boolean expressions.
a) xy + (x + y)z'+ y

b) x + y +(x+y+z)'
c) yz + wx + z + [wz(xy + wz)]

can anyone please help me with the steps...i know what the end should be but I am not clear on how to get there. Thanks!

#### bountyhunter

Joined Sep 7, 2009
2,512
I don't know how you are supposed to solve this system when there are four variables and only three equations.

In general, start with the first equation, multiply all variables out and combine to isolate the equation in terms of one variable (like x) and plug that value into the second equation wherever x appears. Then solve the second equation for y and plug that into the third equation. However, your solution will still have "w" in it.

#### WBahn

Joined Mar 31, 2012
25,060
You need to show YOUR best effort to solve YOUR homework -- that will give us the necessary starting point to help guide you to the solution.

Let's take the first one.

f = xy + (x + y)z'+ y

Q1) What do you know about xy + y ?

Q2) What happens if you distribute the z' over the (x+y), in light of the answer to Q1)?

Also, please lay off the formatting. It makes if very difficult to quote your stuff effectively.

#### shteii01

Joined Feb 19, 2010
4,647
I don't know how you are supposed to solve this system when there are four variables and only three equations.

In general, start with the first equation, multiply all variables out and combine to isolate the equation in terms of one variable (like x) and plug that value into the second equation wherever x appears. Then solve the second equation for y and plug that into the third equation. However, your solution will still have "w" in it.
This is not a system of simultaneous equations.

This is Boolean algebra.
xy is x AND y, they are inputs to the AND gate.
x+y is x OR y, they are inputs to OR gate.
And so on.