On Tuesday, 14 students handed in a permission slip for a field trip. On Thursday, twice as many students handed in their permission slip than on Tuesday. On Friday, an additional 7 students turned in their permission slip. What expression could be used to find the total number of permission slips handed in? 14 x 2 + 7
14 + (2 x 14) + 7
14 + (2 x 7)
14 ÷ (2 x 7) + 14

20 percentage, you can also do it on a calculator.

Ok here we go ..there are plenty of ways to solve such math problems but we will go for the smartest and easiest ..5x+2y=7  -2x+6y=9we rearrange them into the following ..by multiplying the 1st equation by 2 it becomes 10x + 4y = 14we rearrange it and so it becomes 10x = 14 - 4yas for the second equation we multiply it by 5 and rearrange it so it becomes as to the following ..-10x + 30y = 45rearranging so 10x = 30y -45now 10x equals both 14 - 4y and 30y -45so   14 - 4y = 30y -4531 = 26yy= 31/26 = 1.19 or around 1.2so by now we can calculate x easily as  -2x+6y=9so 2x = 6y -9 = 6 * 31/26 - 9 = -1.84  then x = - 0.92 or around -0.9best luck!

Point is the only one not undefined