Answer:
3x+4x=7x
Step-by-step explanation:
basically 3x+4x means 3*x+4*x
thus, we can take x out as a common factor of both
x(3+4)= x*7=7x
or
you can sum the variables with the same element (x is our element in here)
thus,
3x+4x=7x
if it would be 3x+4y you cannot sum them since the elements are different (x and y)
