Question

linear in two variables
$2x + 2y = 15 \: and \: 5x - y = 12$
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Answer 1

Answer:

$2x + 2y = 15 - - - (1) \\ 5x - y = 12 - - - (2) \\ multiply \: equation \:( 2) \: by \: 2 \\ 10x - 2y = 24 - - - (3) \\ add \: equation \: (1) \: and \: (3) \\ 2x + 2y = 15 \\ + \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ 10x - 2y = 24 \\ we \: get \\ 12x = 39 \\ x = \frac{39}{12} \\x = 3.25 \\ put \: x = 3.25 \: in \: equation \: (1) \\ 2x + 2y = 15 \\ 2 \times 3.25 + 2y = 15 \\ 6.5 + 2y = 15 \\ 2y = 15 - 6.5 \\ 2y = 8.5 \\ y = \frac{8.5}{2} \\ y = 4.25 \\ the \: solution \: of \: the \: given \: equation \: is \: (3.25 \: and \: 4.25)$