Respuesta :
4/7 = 21/ (x - 3)
multiply by (x-3) on each side
4(x-3)/7 =21
multiply by 7 on each side
4(x-3) = 21*7
distribute
4x-12 = 147
add 12 to each side
4x = 159
divide by 4
x = 159/4
change back to a mixed number
4 goes into 159 39 times with 3 left over
39 3/4
Choice C
4/7 = 21/(x-3)
Multiply x-3 on to both sides to get
4(x-3)/ 7 =21
Multiply both sides by 7 to get
4(x-3) = 144
Multiply to get
4x - 12 = 144
Add 12 on both sides to get
4x = 156
Divide both by 4 to get
156/4
Or
39
Multiply x-3 on to both sides to get
4(x-3)/ 7 =21
Multiply both sides by 7 to get
4(x-3) = 144
Multiply to get
4x - 12 = 144
Add 12 on both sides to get
4x = 156
Divide both by 4 to get
156/4
Or
39