Solve by Substitution 99x+10.99y=331 , x+y=115

Problem

{[99*x+10.99*y=331],[x+y=115])

Solution

1. Isolate a variable in the second equation. We can solve for x by subtracting y from both sides.

x=115−y

2. Substitute the expression for x into the first equation.

99*(115−y)+10.99*y=331

3. Distribute the constant 99 into the parentheses.

11385−99*y+10.99*y=331

4. Combine the like terms involving y

11385−88.01*y=331

5. Isolate the term with y by subtracting 11385 from both sides.

−88.01*y=−11054

6. Solve for y by dividing both sides by −88.01

y=125.5993637...

Rounding to two decimal places:

y≈125.60

7. Substitute the value of y back into the equation for x

x=115−125.5993637...

x=−10.5993637...

Rounding to two decimal places:

x≈−10.60

Final Answer

(x,y)=(−10.60,125.60)

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