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Question

Do answers differ if we do equations with substitution and then the same equation with elimination ? Because when i solved these two equation x+ 2y+ 1 =0 and 2x-3y -12 =0 with substitution the answers were x= 3 and y = -2 but when i did the same question with elimination i got the answer y as 23 which itself is wrong but how ?
x
+2y+1=0 -------- 12x-3y-12=0 ------- 23(x+2y+1)=03x+6y+1=0 ------ 32(2x-3y-12)=04x-6y-24=0 ----- 4From 3&44x-6y-24=03x+6y+1 = 0- - -________________x -24=0x=24

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Solution

The given equations are :x + 2y = -1 ...12x - 3y = 12 ...2ELIMINATION METHOD :Multiply 1 by 3 and 2 by 2, we get3x + 6y = -3 ....34x - 6y = 24 ....4Adding 3 and 4, we get7x = 21x = 3Put x = 3 in 1, we get3 + 2y = -12y = -4y = -2SUBSTITUTION METHOD :The given equations are :x + 2y = -1 ...12x - 3y = 12 ...2from 1, we getx = -1 - 2y ...3Put the value of x in 2, we get2-1-2y - 3y = 12-2-4y-3y = 12-7y = 14y = -2Now, from 3, we getx = -1-2-2 = -1+4 = 3

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