bill k

Lv 6

# Find value?

Please explain step by step how to mathematically prove the following:

x + y = 100

Find the value of x and y when x = y.

Obviously the answer is 50 but how do I get that answer mathematically?

### 4 Answers

Relevance

- Lisa ALv 78 months ago
YOu have two simultaneous equations in two variables/

x=y

x+y=100

So you can take the first equation, and substitute x for y into the second equation.

x + x = 100

2x = 100

x = 100/2

x = 50

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