Solving Simultaneous Equations 1

1
Solving Simultaneous Equations (1)

• Graphical Solutions
• Solving with 2 linear equations

2
Solving Linear Equations Graphically
3
Solving Linear Equations Graphically (2)

• Problems-
• tedious to draw
• results arent accurate
• need graph paper
• an algebraic method overcomes these problems

4
Algebraic Method 1 Solving by substitution
Most useful method for y mx c graphs
They are both equal to y, so
When x 2
y 2x 1
y 2 ? 2 1
y 5
5
Algebraic Method 1 Solving by substitution
Try this one
They are both equal to y, so
When x 4
y 3x - 1
y 3 ? 4 - 1
y 11
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Algebraic Method 2 Solving by equating
coefficients
Most useful method for ax by c form of
equations
E.g.
(1) 3x 4y 26
Make either coefficient of x or y same size
(2) 7x - y 9
(3)(2)x4 28x - 4y 36
(1) 3x 4y 26
(1)(3) 31x -4y 4y 62
(1)(3) 31x 62
x 2
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Activity

• Time allowed a few minutes
• Turn to page 16 of your Core 1 book and answer
• question D1 (equating coefficients)
• question D4 (substitution)