How do we solve for x here? y = square root(x^2 + 4x) − x?

y = square root(x^2 + 4x) − x

y + x = sqrt( x^2 + 4x)

Square both sides

( x + y)^2 = x^2 + 4x


x^2 + 2xy + y^2 = x^2 + 4x

Subtract x^2 from both sides

2xy + y^2 = 4x

2xy - 4x = - y^2

x( 2y - 4) = - y^2

x = - y^2/(2y - 4)

= y^2/(4 - 2y)

= y^2/2(2 - y)

Cannot solve for x. What do you want solved?

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