Convert the following quadratic equation to vertex form. 2) 3x2 - 12x - 5

3(x - 2)² - 17

Step-by-step explanation:

The equation of a quadratic in vertex form is

y = a(x - h)² + k

where (h, k) are the coordinates of the vertex and a is a multiplier

Using the method of completing the square.

Given

3x² - 12x - 5 ← factor out 3 from the first 2 terms

= 3(x² - 4x) - 5

To complete the square

add/subtract ( half the coefficient of the x- term)² to x² - 4x

= 3(x² + 2(- 2)x + 4 - 4 ) - 5

= 3(x - 2)² - 12 - 5

= 3(x - 2)² - 17 ← in vertex form

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18