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Question
Solve the following simultaneous equations by the substitution method:
x + 3y= 5
7x - 8y = 6
Solution
The given equations are
x + 3y= 5 ....(i)
7x - 8y = 6 ....(ii)
Now, consider equation
x + 3y = 5
⇒ x = 5 - 3y ....(iii)
Substituting the value of x in eqn. (ii), we get
7(5 - 3y) - 8y = 6
⇒ 35 - 21y - 8y = 6
⇒ 35 - 29y = 6
⇒ -29y = -29
⇒ y = 1
Putting the value of y in eqn. (ii), we get
x = 5 - 3(1)
= 5 - 3 = 2
Thus, the solution set is (2, 1).
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