First, you have to distribute the -1 throughout the parentheses, which gives you 7x-3x-10=-46.
Then, you combine 7x and -3x, which gives you 4x-10=-46.
Then, you add 10 to both sides of the equation, which gives you 4x=-36.
FInally, you divide both sides of the equation by 4, which gives you x=-9.