Equations in Two Variables

Graphically, the pair of equations 6x – 3y + 10 = 0 , 2x – y + 9 = 0 represents two lines which are

• intersecting at exactly one point

• intersecting at exactly two points.

• coincident. 

•  parallel.

The pair of equations x + 2y + 5 = 0 and –3x – 6y + 1 = 0 have  

•  a unique solution

• exactly two solutions

• infinitely many solutions

• No solution

The pair of equations x = a and y = b graphically represents lines which are  

• parallel 

•  intersecting at (b, a)

•  coincident

•  intersecting at (a, b)

For which value(s) of k will the pair of equations kx + 3y = k – 3 12x + ky = k have no solution?

• 6

• −6

• ± 6

• 4

How many linear equations in x and y can be satisfied by x = 1 and y = 2

• Only one

• Two

• Infinitely many

• Three

Tell whether the ordered pair is a solution of:
y = -3x + 9
(2, 3) 

• Yes!

• No! 

Tell whether the ordered pair is a solution of:
y = -3x + 9
(3, 1) 

• Yes!

• No!

Tell whether the ordered pair is a solution of:
y = -3x + 9
(1, 3) 

• Yes!

• No!

Tell whether the ordered pair is a solution of:
y = -3x + 9
(-3, 18) 

• Yes!

• No!

Which variable represents the input?

• x

• y

• z