Question

if 15x+12y=9;12x+15y=6 find x-y=?​

Answer 1

$\red {\huge {\underline{ \frak{Your \: answEr : }}}}$

$\blacksquare$ 15x + 12y = 9 (¡)

$\blacksquare$ 12x + 15y = 6 (¡¡)

Multiplying (¡) with 4 and (¡¡) with 5 .

$\longrightarrow$ 60x + 48y = 36

$\longrightarrow$ 60x + 75y = 30

⠀⠀⠀- ⠀⠀⠀ - ⠀⠀ -

______________________________

$\longrightarrow$ -27y = 6

$\large{\longrightarrow \tt{y = \frac{ -6}{27} }}$

$\blue{\large \longrightarrow \tt{y = \frac{ - 2}{9} }}$

Putting Value of y in (¡)

$\longrightarrow$ 15x + 12y = 9

$\longrightarrow \tt{15x + 12 \times \frac{ - 2}{9} = 9}$

$\longrightarrow \tt{15x + 4 \times \frac{ - 2}{3} = 9}$

$\longrightarrow \tt{45x - 8 = 27}$

$\longrightarrow \tt{45x = 35}$

$\large\longrightarrow \tt{x = \frac{35}{45} }$

$\blue {\large\longrightarrow \tt{x = \frac{7}{9} }}$

━━━━━━━━━━━━━━━━━━━━━

$\large\tt \star \: {(x - y)}$

$\large\tt \star \:{ (\frac{ - 2}{9} - \frac{7}{9} ) }$

$\large\tt \star \:{( \frac{ - 2 - 7}{9}) }$

$\large\tt \star \:{ \frac{ - 9}{9} }$

$\pink{\huge\tt \star \: \boxed{\:{ - 1}}}$

$\huge{\red{\ddot{\smile}}}$