Answer:
the correct choice is marked
Step-by-step explanation:
Let x represent the smaller number. Then the larger number is 8x, and the difference is ...
8x -x = 280
7x = 280 . . . . . simplify
x = 40 . . . . . . divide by 7
The larger number is 8x = 8(40) = 320.
_____
<em>Additional comment</em>
Effectively, we have solved for the multiplier (40) that gives the ratio with 320 on top and a difference between top and bottom of 280:

Xy is the number
A) x + y = 7
B) 10y + x = 10x + y + 9
collecting terms of equation B
B) -9x + 9y = 9
multiplying A) by 9
A) 9x + 9y = 63 then adding it to equation B)
B) -9x + 9y = 9
18y = 72
y = 4
x = 3
The number is 34
13x + 7x - 4x = -40
combine like terms o0n the left
16x = -40
divide both sides by 16
x = -5/2 or -2.5
It’s weird. that’s what it is