Question

3x + 5. - 4x = 7x +13 - x

Answer 1

21x=5
x= 5/21
5/21 = 4.2

Answer 2

$3x + 5. - 4x = 7x + 13 - x \\ - x + 5 = 6x + 13 \\ - x - 6x = 13 - 5 \\ - 7x = 8 \\ x = \frac{8}{ - 7 }$