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Engage in a comprehensive lesson on solving simultaneous equations using the substitution method and graph plotting. Recap on elimination method and practice with various difficulty levels. Explore step-by-step examples and answer practice questions to master these techniques effectively.
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Equations Objectives for today’s lesson : • Recap on solving SE’s using elimination • Solving SE’s using substitution
Starter Choose two of these problems to solve : 3x + y = 21 Easy x + y = 11 4x + 2y = 24 Medium 3x + y = 14 2x + 3y = 27 Hard 3x + 2y = 23
Starter Choose two of these problems to solve : 3x + y = 21 x = 5, y = 6 x + y = 11 4x + 2y = 24 x = 2, y = 8 3x + y = 14 2x + 3y = 27 x = 3, y = 7 3x + 2y = 23
Using substitution There is another way to solve simultaneous equations : Example : x – 3y = 14 (1) x + y = 22 (2)
Using substitution There is another way to solve simultaneous equations : Example : x – 3y = 14 (1) x + y = 22 (2) Rearrange equation (1)
Using substitution There is another way to solve simultaneous equations : Example : x – 3y = 14 (1) x + y = 22 (2) Rearrange equation (1) x = 14 + 3y
Using substitution There is another way to solve simultaneous equations : Example : x – 3y = 14 (1) x + y = 22 (2) Rearrange equation (1) x = 14 + 3y Now, substitute this in equation (2)
Using substitution There is another way to solve simultaneous equations : Example : x – 3y = 14 (1) x + y = 22 (2) Rearrange equation (1) x = 14 + 3y Now, substitute this in equation (2) 14 + 3y + y = 22
Using substitution There is another way to solve simultaneous equations : Example : x – 3y = 14 (1) x + y = 22 (2) Rearrange equation (1) x = 14 + 3y Now, substitute this in equation (2) 14 + 3y + y = 22 So, 14 + 4y = 22
Using substitution There is another way to solve simultaneous equations : Example : x – 3y = 14 (1) x + y = 22 (2) Rearrange equation (1) x = 14 + 3y Now, substitute this in equation (2) 14 + 3y + y = 22 So, 14 + 4y = 22 4y = 8 y = 2
Substitution Question Practice x + 3y = 31 x + y = 13 x + 5y = 51 x + y = 11 x + 4y = -3 x + 2y = 1
Substitution Question Practice - Answers x + 3y = 31 x = 4, y = 9 x + y = 13 x + 5y = 51 x = 1, y = 10 x + y = 11 x + 4y = -3 x = 5, y = -2 x + 2y = 1
To finish There is one final way of solving these equations. To do this, you need to be able to plot straight line graphs.
To finish Plot these straight line graphs : y = x y = 2x + 1 y = 1 - x y = 3x – 1
To finish y = x y = 2x + 1 y = 1 - x y = 3x - 1