Q2 of 102 Page 44

Solve the following equations by the method of elimination (by substitution)

x + 2y = -1


2x – 3y = 12

We have

x + 2y = -1 …(i)


2x – 3y = 12 …(ii)


From equation (i),


x + 2y = -1


x = -2y – 1 …(iii)


Substituting the value of x from equation (iii) in equation (ii), we get


2(-2y – 1) – 3y = 12


-4y – 2 – 3y = 12


-7y – 2 = 12


-7y = 2 + 12


-7y = 14



y = -2


Putting this value of y in equation (iii), we get


x = -2(-2) – 1


x = 4 – 1


x = 3


Thus, we get the solution as x = 3 and y = -2.


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