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

Select the correct answer Which equation when solved gives 8 for the value of x OA 3 14 OB 593112 OC 212r4 OD 5714 class=

Respuesta :

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

[tex]\frac{10x-3x}{4}=\frac{28-7}{2}[/tex][tex]\frac{7x}{4}=\frac{21}{2}[/tex][tex]x=\frac{21}{2}\times\frac{4}{7}=6[/tex]

For B

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

collect like term and solve for x

[tex]\frac{5}{4}x-\frac{3}{2}x=-12+9[/tex][tex]=\frac{5x-6x}{4}=-3[/tex][tex]-\frac{x}{4}=-3[/tex][tex]x=12[/tex]

For C

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

collect like term and then solve for x

[tex]\frac{5}{4}x-\frac{3}{2}x=-4+2[/tex][tex]\frac{5x-6x}{4}=-2[/tex][tex]-\frac{x}{4}=-2[/tex][tex]x=8[/tex]

For D

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

collect like term and solve for x

[tex]\frac{5}{4}x-\frac{3}{4}x=14+7[/tex][tex]\frac{2x}{4}=21[/tex][tex]x=42[/tex]

Therefore, the correct option is C