How many solutions are there to 3x-10 (x+2) = 13-7x

This is the following way to solve this problem:

3x-10 (x+2) = 13-7x

3x-10x-20=13-7x (multiply 10 times what's in the parentheses)

-7x-20=13-7x (subtract 3x from - 10x)

-7x-20-13=-7x (since the 13 is positive, when we move it to the other

side, we change it's sign, so now we subtract 13 from 20

-7x-7=-7x

-7=-7x+7x (we do the same thing we did above, now with the - 7x)

-7=x

x=-7

Answer: x = - 7

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:)