Algebra problems plz help!?

Question

how would i do this!

10 points best answer!

pleease explain how I would solve this equation by graphing.

x^2+3x+4=0

complete the square:

x^2-8x-3=0

find the axis of symmetry & vertex of graph of function & tell weather it is minimum or maximun.

y=2x^2+8x+3

y=1/2x^2-2x+5

thanks plz so step-by-step so i can understand!

Answer 1

miss jenny

i know only the 2nd equ i.e. completing square

x^2 - 8x-3 =0 ; x^2 is a prefect square

so a=x , -2ab =-8x

=>-2xb=-8

=b=4

b^2=16

add 16 on both the sides

x^2 - 8x+16=19

(x-4)^2=19

x-4 =plus OR minus sq root of 19

x=4 plus OR minus sq root of 19

x=4+sq root of 19

          OR

x=4-sq root of 19

thank you

Answer 2

x+2+3x+4=>4x+6=0

                 =>x=-6/4=-3/2.

x+2-8x-3=>-7x-1=0

               =>x=-1/7.