There are 20 students in a math class who have brown hair. This represents 80 percent of the students in the class. Which equation can be used to find the total number of students in the math class? StartFraction 20 times 100 Over 80 times 100 EndFraction = StartFraction 2000 Over 8000 EndFraction
StartFraction 80 times 5 Over 20 times 5 EndFraction = StartFraction 400 Over 100 EndFraction
StartFraction 80 divided by 4 Over 100 divided by 4 EndFraction = StartFraction 20 Over 25 EndFraction
StartFraction 20 divided by 1 Over 80 divided by 1 EndFraction = StartFraction 20 Over 80 EndFraction

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!

444(2)4-2(7)2+40=? 8(4)-14(2)+40=? 32-28+40=? 4+40=? 44