x+y=240 and 5x+8y=1614

Question

solve by elimination

Answer 1

Elimination method

 Given equation x+y = 240 -------> (1)

Multiply to each side by negitive 5.

-5x-5y = -1200 ----------> (3)

And 5x+8y = 1614 ----------> (4)

To eliminate the x value, add the equations (3)&(4).

-5x-5y = -1200

5x+8y = 1614

____________

3y = 414

Divide to each side by 3.

3y/3 = 414/3

y = 138

Substitute the y value in equation x+y = 240.

x+138 = 240

Subtract 138 from each side.

x+138-138 = 240-138

x = 102

Solution is x = 102, y = 138.