Final answer:
To find the missing number so that the equation has no solution, we need to equate the coefficients of the x terms on both sides of the equation. The missing number is 0.
Step-by-step explanation:
To find the missing number so that the equation has no solution, we need to equate the coefficients of the x terms on both sides of the equation. We have 4x on the left side and x + 6x on the right side. Combining like terms, we get 4x = 7x. In order for the equation to have no solution, the coefficient of x on both sides must be equal, which means 7x should be 4x. Therefore, the missing number is 0.