Question

Solve the system using substitution.

Answer 1

Answer:

C) (3,9),(-4,16)

Step-by-step explanation:

hello :

the system is :   y = 7x - 12

                         y = x²

x²=7x-12

x²-7x+12=0

∆ = b² - 4ac     a = 1    b= -7    c=12

∆ = (-7)² - 4(1)(12) = 49-48 = 1

X1 = (-b-√∆)/2a= (7-1)/2=3

X2 = (-b+√∆)/2a= (7+1)/2=4

but : y=x²

if : x= 3    y=9

if : x=4    y=16

two solutions :  

answer :C) (3,9),(-4,16)