Question

Solve the system by graphing.
2x + y = 6
4x + 2y = 12

Answer 1

well before you graph the lines... take the 2nd line and divide every term by 2, what do you get...?

Answer 2

2x+y=12

Answer 3

2x+y=6

Answer 4

nearly... you need to halve every term... including the 12...

so what do you get..?

Answer 5

great... so what can you say about the 2 lines... before graphing...?

Answer 6

That they are the same.

Answer 7

yeap... so you only need to graph 1 line... and the have an infinite numbers of solutions or points of intersection

Answer 8

Thanks :D
C) {(x, y)| 2x + y = 6}

Answer 9

Given 2x + y = 6.............(1)
4x + 2y = 12 …..............(2)
divide equation (2) by 2
=>2x+y=6
this is same as the equation (1) hence there is only one equation
=>y=-2x+6
where slope m=-2
and c=6

See also CBSE Sample Paper http://goo.gl/TqhFe1