If 5x-3y=23 and 4x-4y=20, which is the value of x+y?

3

Step-by-step explanation:

5x-3y=23

4x-4y=20

I'm going to try to set this up for elimination. I notice the bottom equation contains terms that are divisible by 4 so I'm going to divide both sides by 4 on that last equation only...

5x-3y=23

 x-  y=  5

Now I'm going to multiply the bottom equation by -3 so the y terms will be opposite. When you add opposites you do get 0.  That is the whole point of elimination.  

5x-3y=23

-3x+3y=-15

adding

2x+0=8

2x    =8

 x    =4

So  using that second equation x-y=5 I will find y given that x=4.

4-y=5

-y =1

 y=-1

So the solution to the system is (4,-1)

You are asked to find x+y

So x+y=4+(-1)=3

a - base

b - exponent

so,

the answer is:

the answer is:

to solve the problem, we need to remember the quotient of power property, it's defined by the following relation:

if we have a quotienf of powers that have the same base, we need to keep the same base and subtract the exponent of the denominator power to the exponent of the numerator power.

so, we are given the expression:

then, calculating we have:

hence, the answer is:

have a nice day!