Question

7x-15y=2 x+2y=3 find the value of x and y from substitution method

Answer 1

7x-15y=3
so 7x=15y+3
so x=(15y+3)/7......(i)
put this in second equation
2×(15y+3)/7+2y=3
so 44y=15
so y=15/44
put this in (i)
you get x=357/308

Answer 2

Answer:

$7x - 15y = 2 \\ \: \implies7x = 2 + 15y \\ \implies \: x = \frac{2 + 15y}{7} \: \: \: \: \: \rightarrow(i) \\ \\ x + 2y = 3 \\ \implies\frac{2 + 15y}{7} + 2y = 3 \: (putting \: x = \frac{2 + 15y}{7} ) \\ \implies \frac{2 + 15y + 14y}{7} = 3 \\ \implies15y + 14y = 3 \times 7 - 2 \\ \implies29y = 21 - 2 \\ \implies \: y = \frac{19}{29} \\ \\ \\ \: \: substituting \: the \: value \: of \: y \: in \: equation \: (i) \\ 7x - 15 \times \frac{19}{29} = 2 \\ \implies7x - \frac{285}{29} = 2 \\ \implies7x = 2 + \frac{285}{29} \\ \implies7x = \frac{58 + 285}{29} \\ \\ \: \implies7x = \frac{343}{29 } \\ \\ \implies \: x = \frac{343}{203} \\ \\ \implies \: x = \frac{49}{29} \\ \\ \therefore \: x = \frac{49}{29} \\ \\ y = \frac{19}{29}$