# What is the vertex form of y= (5x - 1) (x+1) ?

The vertex form is $y = 5 {\left(x + \frac{2}{5}\right)}^{2} - \frac{9}{5}$
$y = \left(5 x - 1\right) \left(x + 1\right) \mathmr{and} y = 5 {x}^{2} + 4 x - 1$ Now comparing withh the general form $y = a {x}^{2} + b x + c$ we get a=5; b=4 ; c= -1 The x cordinate of Vertex is $= - \frac{b}{2} \cdot a \mathmr{and} - \frac{4}{10} = - \frac{2}{5}$ To get y co-ordinate of veryex putting $x = - \frac{2}{5}$ in the equation $y = 5 \cdot {\left(- \frac{2}{5}\right)}^{2} + 4 \cdot \left(- \frac{2}{5}\right) - 1 = 5 \cdot \left(\frac{4}{25}\right) - \frac{8}{5} - 1 = - \frac{9}{5}$ So The vertex form is $y = 5 {\left(x + \frac{2}{5}\right)}^{2} - \frac{9}{5}$graph{5x^2+4x-1 [-10, 10, -5, 5]}[Answer]