F.1的一條maths 題,快~~

My answer:

Let x be the number.
[(2y-6)+1/2y]x2=7x4
2[2y-6+1/2y]=7x4
(2*2y)-(2*6)+(2*1/2y)=28
4y-12+y=28
4y+y-12=28
4y+y=28+12
5y=40
5y/5=40/5
y=8
*The number is 8.

I hope my answer can help you.

【(2y-6)+1/2y】x2=7x4
2x(2y-6) + 1/2y x 2 = 28
(4y-12) + y = 28
5y - 12 = 28
5y = 28 + 12
5y = 40
y = 40 / 5
y = 8