Question

x-5y=4 ; 2x+y=7 find the solutions by sunstitution method​

Answer 1

x-5y=4

2x+y=7

x= 4+5y

Substitute this in the 2 equation

2(4+5y)+y=7

8+10y+y=7

11y=7-8

Y=-1/11

2x+ -1/11=7

2x=7+1/11

x=(78/11)/2

=78/22

=39/11

Answer 2

$x - 5y = 4 \: \: \: \: ......(1) \\ \\ 2x + y = 7 \: \: \: \: ......(2) \\ \\ \\ \\ \\ from \: (1) \: \\ \\ x = 4 - 5y \\ \\ \\ by \: putting \: the \: value \: of \: x \: in \: (2) \: we \: get \: - - \\ \\ \\ 2(4 - 5y) + y = 7 \\ \\ \\ = > 8 - 10y + y = 7 \\ \\ \\ = > - 9y = - 1 \\ \\ \\ = > y = \frac{1}{9} \\ \\ \\ \\ \\ by \: putting \: the \: value \: of \: y \: in \: (1) \: we \: get \: - - - \\ \\ \\ x - 5 \times \frac{1}{9} = 4 \\ \\ \\ = > x - \frac{5}{9} = 4 \\ \\ \\ = > \frac{9x - 5}{9} = 4 \\ \\ \\ = > 9x - 5 = 36 \\ \\ \\ = > 9x = 41 \\ \\ \\ = > x = \frac{41}{9}$

Therefore ,

x = $\frac{1}{9}$

x = $\frac{1}{9}$ y = $\frac{41}{9}$