y = 2(x - 2)² - 7
the equation of a parabola in vertex form is
y = a(x - h)² + k
where (h, k) are the coordinates of the vertex and a is a multiplier
to obtain this form use the method of ' completing the square'
the coefficient of the x² term must be 1 → (factor out 2)
y = 2(x² - 4x +
)
add/subtract (
coefficient of the x- term)² to x² - 4x
y = 2(x² + 2(- 2) + (- 2)² - (- 2)² +
)
y = 2(x - 2)² + 2( -
)= 2(x - 2)² - 7