(x^2 / x) = x.
Write x as the first partial quotient. Multiply x by the divisor x+4. Subtract from the first two terms of the dividend. Bring down the next term.
x(x+4)=x^2+4x, so when you subtract this, it like this:
x^-6x-(x^2+4x)= what? THEN you bring down the next term and repeat the process.