6w-10 represents the total amount of fence will need to complete the rectangle of fence in his yard. The fence will need two lengths and 2 widths to complete the rectangle. If the width is w, and the length is 2w-5, then the total for the rectangle would be w+w+2w-5+2w-5 which simplifies to 6w-10.
3 - x = 10
-x = 10 - 3
-x = 7
x = -7 <===
Just do 8 divided by two and then add 25 to that and you get that answer which is $29
#9 You have to make the fraction a decimal, then multiply 11.8 by 6.5. This is because 11.8 is per hour.
#10 here is a hint, one quarter of an hour is 15 minutes. again change the fraction to a decimal
#11 just multiply the 2 numbers
1.4
×2.9
---------
126
+ 280
------------------
3.06