Question

if 5x+4y = 23 and 3x-y=7, what is the value of x

Answer 1

Answer:

Given equations

3

x

−

4

y

=

−

23

...

...

(

1

)

5

x

+

y

=

−

7

...

...

...

(

2

)

Multiplying (2) by

4

& adding to (1), we get

3

x

−

4

y

+

4

(

5

x

+

y

)

=

−

23

+

4

(

−

7

)

23

x

=

−

51

x

=

−

51

23

setting the value of

x

in (1), we get

3

(

−

51

23

)

−

4

y

=

−

23

4

y

=

23

−

153

23

y

=

376

23

⋅

4

y

=

94

23

Hence the solution is

x

=

−

51

23

,

y

=

94

23

Step-by-step explanation:

hope it helps

Answer 2

Given,

• $5x + 4y = 23$

• $3x - y = 7$

To Find,

• The value of 'x'.

Solution,

As given,

• $5x + 4y = 23 \: \: \: \: \: ...(1)$

• $3x - y = 7 \: \: \: \: \: ...(2)$

Solving by Elimination Method,

Multiplying Eq [2] by 4 to make the coefficients of 'y' equal as,

$: \longmapsto 4(3x - y) = 4(7) \\ \\ : \longmapsto 12x - 4y = 28 \: \: \: \: \: ...(3)$

Adding Eq [1] and Eq [3] to eliminate 'y' and Finding the value of 'x' as,

$: \longmapsto (5x + 4y) + (12x - 4y) = 23 + 28\\ \\ : \longmapsto 5x + 12x + 4y - 4y = 51 \\ \\ : \longmapsto 17x = 51 \\ \\ : \longmapsto x = \frac{51}{17} \\ \\ : \longmapsto \boxed{ x = 3}$

Substituting the value of 'y' in Eq [2] and Finding the value of 'x',

$: \longmapsto 3x - y = 7 \: \: \: \: \: ...(2) \\ \\ : \longmapsto 3(3) - y = 7 \\ \\ : \longmapsto 9 - y = 7 \\ \\ : \longmapsto9 - 7 = y \\ \\ : \longmapsto \boxed{y = 2}$

Therefore,

• The values of 'x' and 'y' are 3 and 2 respectively.

Required Answer,

• The values of 'x' and 'y' are 3 and 2 respectively.