Solve by Substitution 2x+2y=90 , x-y=15

Problem

{[2*x+2*y=90],[x−y=15])

Solution

1. Isolate a variable in the second equation by adding y to both sides.

x=y+15

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

2*(y+15)+2*y=90

3. Distribute the constant into the parentheses.

2*y+30+2*y=90

4. Combine the like terms on the left side.

4*y+30=90

5. Subtract 30 from both sides of the equation.

4*y=60

6. Divide by 4 to solve for y

y=15

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

x=15+15

8. Calculate the final value for x

x=30

Final Answer

(x,y)=(30,15)

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