Question

What is the value of Dx for solving the simultaneous equations 3x + 2y = 11 and 7x - 4y = 9 by cramers rule

Answer 1

Answer:

hope it's helpful to you GM :))

Step-by-step explanation:

Given equations are 3x+2y+11=0 and 7x−4y=9

⟹3x+2y=−11 and 7x−4y=9

By Cramer's rule,

D=

∣

∣

∣

∣

∣

∣

3

7

2

−4

∣

∣

∣

∣

∣

∣

=−12−14=−26

D

x

=

∣

∣

∣

∣

∣

∣

−11

9

2

−4

∣

∣

∣

∣

∣

∣

=44−18=26

D

y

=

∣

∣

∣

∣

∣

∣

3

7

−11

9

∣

∣

∣

∣

∣

∣

=27+77=104

Now, x=

D

D

x

=

−26

26

=−1

y=

D

D

y

=

−26

104

=−4

Hence, x=−1,y=−4.

Answer 2

Answer:

$3x + 2y = 11 \\ </p><p>7x - 4y = 9 \\ \\ from \: equation \: (1) \\ y = \frac{11 - 3x}{2} \\ \\ substituting \: the \: value \: of \: y \: in \: equation \: (2) \\ 7x - 4( \frac{11 - 3x}{2}) = 9 \\ 7x - 22 - 6x = 9 \\ x - 22 = 9 \\ x = 9 + 22 \\ x = 31 \\ \\ from \: equation \: (1) \\ y = \frac{11 - 3x}{2} = \frac{11 - 3 \times 31}{2} \\ = \frac{11 - 33}{2} = - \frac{22}{2} = - 11$