## Introductory Algebra for College Students (7th Edition)

Bill Gates income at that time was \$81 billion and Warren Buffets earned \$67 billions.
This problem uses a system of equations. The first is the combination of y (Bill Gates) and x (Warren Buffet's). And the sum is \$148 billion dollars. This is mathematically written$x+y=148$. We are also told that Bill Gate's net worth was$x+14$We can derive two equations from this information and the original equation, using the relationship$y= x+14$: $$x + x+ 14 = 148$$ $$2x + 14 = 148$$ Subtract by 14 on both sides, which gives $$2x+ 14 -14 = 148 - 14$$ $$2x= 134$$ Divide by 2 $$x= \frac{134}{2}$$ $$x= 67$$ To get the value of y, use the original equation,$x+y=168$. $$y + 67 = 168$$ Subtract 67 from both sides. $$y + 67 -67 = 168 -67$$ y= 81 This the answer is: Bill Gates income at that time was \$81 billion and Warren Buffets earned \\$67 billions.