Step-by-step explanation:
10 + 3x = 30 + 7x
collect terms that look alike on one side.
we can see that 3x & 7x have something in common which is x.
so move one of these to either of the equality's sides.
0 = 30 + 7x -10 - 3x
i changed the sign of 3x to -3x & 10 to -10 because we'll have to subtract 3x or 10 from the left side inorder for them to vanish & appear on the right hand side.
collect like terms.
0 = 30 - 10 + 7x - 3x
0 = 20 + 4x
take 20 to the left side to find x by dividing by 4.
20 = 4x
20 / 4 = x
5 = x
