I need help with algebra

x = -1 and y = 6

Step-by-step explanation:

using x = -b/2a

x = -4 / 2(2)

x = -1

y = 2(-1)² + 4(-1) + 8

y = 2 - 4 + 8

y = 10 - 4

y = 6

Insert a number into the x,

the middle column, you just substitute,

and the last column, you enter what x and y is.

Step-by-step explanation:

For example,

if x was 5, I would write 5 under the column,

under the y=2x+5 column, you would write y=2*5+5,

and under the last column you would write (5, 15)