Question

Slove the linear equation in Cramer rule 3x+4y+5z;2x-y+8z=13;5x-2y+7z

Answer 1

Answer:

broo I am not sure that it is correct .......

Step-by-step explanation:

Given equations are 3x+4y+5z=18,2x−y+8z=13,5x−2y+7z=20

D=

∣

∣

∣

∣

∣

∣

∣

∣

3

2

5

4

−1

−2

5

8

7

∣

∣

∣

∣

∣

∣

∣

∣

=3(−7+16)−4(14−40)+5(−4+5)

=3(9)−4(−26)+5(1)=27+104+5=136

D

1

=

∣

∣

∣

∣

∣

∣

∣

∣

18

13

20

4

−1

−2

5

8

7

∣

∣

∣

∣

∣

∣

∣

∣

=18(−7+16)−4(91−160)+5(−26+20)

=18(9)−4(−69)+5(−6)=162+276−30=408

D

2

=

∣

∣

∣

∣

∣

∣

∣

∣

3

2

5

18

13

20

5

8

7

∣

∣

∣

∣

∣

∣

∣

∣

=3(91−160)−18(14−40)+5(40−65)

=3(−69)−18(−26)+5(−25)=−207+468−125=136

D

3

=

∣

∣

∣

∣

∣

∣

∣

∣

3

2

5

4

−1

−2

18

13

20

∣

∣

∣

∣

∣

∣

∣

∣

=3(−20+26)−4(40−65)+18(−4+5)

=3(6)−4(−25)+18(1)=18+100+18=136

Now, x=

D

D

1

=

136

408

=3

y=

D

D

2

=

136

136

=1

z=

D

D

3

=

136

136

=1

Hence, the solution for the system is (3,1,1).