Question

Solve the following systems of equations by using the method of substitution.
2) x + 2y = 7; 2x + 4y = 14
3) x + 2y = 9; x + 4y = -5
4) 2x = y +7; x + y + 1 = 0
5) x = y - 1; x - 2y = -2
6) 3m- n = 5; 2m+n=5
7) 0.2x + 0.3y = 1.3 ; 0.4x + 0.5y = 2.3
8) y = x + 6, 2x + 3y = 3
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Answer 1

3,4and 5 solved .

but 2 equations

x+2y=7

2(x+2y)=(7)2

2x+4y=14

so , no Solution