Question

if 5x - 7y = 14 and 5x + 7y = 56 , then what is the value of x + y ​

Answer 1

Answer:

$5x - 7y + 5x + 7y = 56 \\ 10x = 56 \\ x = 56 \div 10 \\ x = 5.6 \\ 5(5.6) - 7y = 14 \\ 28 - 7y = 14 \\ - 7y = 14 - 28 \\ - 7y = - 14 \\ y = 2 \\ x + y = 5.6 + 2 \\ = 7.6$