-2x(-4)=8x
-9(-4)=36
8x+36 is the answer
She made a mistake in steps 3-4
10% of 640 is 64. So 640-64= 576 fans. Then after the five touchdowns 26% of 576 is 144 . So 576-144= 432 fans left
2ab - 3a = a.(2b-3)
now the same thing
let's say n=1
a.(2b-3) + n.(2b-3) = (2b-3).(a+n)
Understood?
Answer: 4%-16000 and 9.5%-30000
Why:
1) x+y=46000
x=46000-y
2) 4%x+9,5%y=3490;
4x + 9.5y=349000; so 4*(46000-y)+9.5y=349000;
5.5y=165000
y=30000
x=46000-30000=16000