Question

Select the correct answer. Which equation, when solved, gives 8 for the value of x? OA. +3 = =+14 OB. 5-9=31-12 OC. 21-2=r-4 OD. 5.-7=*=+14

Answer 1

Let's solve for each and see which gives 8

For A

5/2 x + 7/2 = 3/4 x + 14

collect like term aand solve for x

5/2 x - 3/4 x = 14 - 7/2

`(10x-3x)/(4)=(28-7)/(2)`
`(7x)/(4)=(21)/(2)`
`x=(21)/(2)*(4)/(7)=6`

For B

5/4 x - 9 = 3/2 x -12

collect like term and solve for x

`(5)/(4)x-(3)/(2)x=-12+9`
`=(5x-6x)/(4)=-3`
`-(x)/(4)=-3`
`x=12`

For C

5/4 x - 2 = 3/2 x - 4

collect like term and then solve for x

`(5)/(4)x-(3)/(2)x=-4+2`
`(5x-6x)/(4)=-2`
`-(x)/(4)=-2`
`x=8`

For D

5/4 x - 7 = 3/4 x + 14

collect like term and solve for x

`(5)/(4)x-(3)/(4)x=14+7`
`(2x)/(4)=21`
`x=42`

Therefore, the correct option is C