Question

Find the vertex of y=(x+5)(x+3) in Standard form

Answer 1

The vertex is at (−4,−1) .

Explanation:

y = ( x + 5 ) ( x + 3)

y = x
`{}^(2)` + 8x + 15

The standard form of the equation for a parabola is y = ax
`{}^(2)` + bx + c

By comparing the two equations, we see that

a = 1 , b = 8 , and c = 15.

The x -coordinate of the vertex is at

x = -b/(2a) = -8/(2×1) = -8/2 = -4

To find the y -coordinate of the vertex, we insert

x = −4 into the equation.

y = (x+5)(x+3) = (-4+5)(-4+3) = 1(-1) = -1

The vertex is at ( −4,−1 ).