Together, a double cheeseburger and a small order of fries cotains 690 calories. the fries have half as many calories as the double cheeseburger. determine the number of calories in each

X+y=690
y=x/2

x= calories in double cheeseburger
y= calories in fries

set both problems to y then set them equal to each other like so...
y=690-x
y=x/2

690-x=x/2       times by 2
1380-2x=x       Add 2x to other side
1380=3x         divid by 3
x=460

To find y plug 460 into y=x/2
y=460/2
y=230

cheeseburgers have 460 calories and fries have 230 calories.

Ithink its 126 hope its