Question

hiiii.....pls .....solve

Answer 1

Hello ❤️

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Just isolate one of the variables, and start plugging it into the other equations. 

3x - 4y + z = 7 

⇒ z = -3x + 4y + 7 

Now plug it into another equation 

2x - (-3x + 4y + 7) + 3y = 19 

⇒ 2x + 3x - 4y - 7 + 3y = 19 

⇒ 5x - y - 7 = 19 

⇒ 5x - y = 26

⇒ -y = -5x + 26 

⇒ y = 5x - 26 

x + 2(5x - 26) + 2 {-3x + 4(5x - 26) + 7} = 24 

⇒ x + 10x - 52 - 6x + 40x - 208 + 14 = 24 

⇒ 45x = 270 

∴ x = 6 

y = 5(6) - 26 

⇒ y = 30 - 26 

∴ y = 4 


z = -3x + 4y + 7 

⇒ z = -3(6) + 4(4) + 7 

⇒ z = -18 + 16 + 7 

∴ z = 5 

So x = 6 , y = 4 , and z = 5 

The value of Z is 5.


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check your answer. 

x + 2y + 2z = 24 

6 + 2(4) + 2(5) = 24 

6 + 8 + 10 = 24 

24 = 24

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Hence, the value of z is 5.

Option ( B )

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Thanks for the question !

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Answer 2

Hi there !

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Given :

3x - 4y + z = 7 ......... (i)

2x - Z + 3y = 19 .......... (ii)

x + 2y + 2z = 24......... (iii)

To find ;

What is the value of z?

Solution :

Take one of the equation, i. e.,

3x - 4y + z = 7

⇒ z = - 3x + 4y + 7......... (iv)

Now, substituting the value of z in eqⁿ (ii)

2x - z + 3y = 19

⇒ 2x - ( - 3x + 4y + 7 ) + 3y = 19

⇒ 2x + 3x - 4y - 7 + 3y = 19

⇒ 5x - y - 7 = 19

⇒ 5x - y = 26

⇒ y = 5x - 26 ........... (v)

Now putting the value of y and z in eqⁿ (iii)

x + 2y + 2z = 24

⇒ x + 2 ( 5x - 26 ) + 2 [ - 3x + 4 ( 5x - 26 ) - 7]

⇒ x + 10x - 52 - 6x + 40x - 208 + 14 = 24

⇒ 45x = 270

⇒ x = 270 / 45

⇒ x = 6

Now,

Putting the value of x in ( v )

y = 5x - 26

⇒ y = 5 × 6 - 26

⇒ y = 30 - 26

⇒ y = 4

And,

Putting the value of y in ( iv ),

z = - 3x + 4y + 7

⇒ z = - 3 * 6 + 4 * 4 + 7

⇒ z = - 18 + 16 + 7

⇒ z = 23 - 18

⇒ z = 5

Hence, the value of z is 5.

Option ( B ) is correct.

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Thanks for asking question !

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