Question

4s+5t=9,6s+4t=9
isko bilopan se hal karo​

Answer 1

$4s+5t=9 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \cdots(1) \\ 6s+4t=9\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \cdots(2)$

$\rm{}Multiplying \: {eq}^{n} \:( 1) \: by \: 3 \: and \: {eq}^{n} \:( 2) \: by \: 2 \: \: \&$

$\text{Simultaneously subtracting the obtained } \rm {eq}^{n} \: (1) \: \: from \: \: {eq}^{n} \: (2)$

$\bf \cancel{12s} + 12t - \cancel{12s } - 15t = 18 - 27 \\ \bf \: \: \: \: \: - 3t = 9 \\ \bf{t = \frac{9}{ - 3} } = \red{ - 3}$

Now, Using Eq (2),

$\bf \: s = \frac{9 - 4t}{6} \\ \\ \bf= > \frac{9 - 4( - 3)}{6} = \frac{9 + 12}{6} \\ \\ \bf = > \frac{21}{6} \: \: = \frac{7}{2} \: \: = \red{3.5}$

Hence,

• s = 3.5
• t = -3