Question

If x= 4y + 3 and y = -2x - 3, what is the value of xy?

Answer 1

Given that :-

• x = 4y +3

• y = -2x -3

To Find :-

• Value of x.y

Solution :-

→ x = 4y + 3 equation 1st

→ y = -2x -3 equation 2nd .

Now putting the value of x from first equation to second equation.

→ y = -2(4y +3 ) -3

→ y = -8y - 6 - 3

→ y + 8y = -9

→ 9y = -9

→ y = -1

Now putting the value of y in equation first .

→ x = 4(-1) + 3

→ x = -4 + 3

→ x = -1

Now multiply and X and y.

→ x.y = -1(-1)

→ x.y = 1 .

Answer 2

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Given,

• x = 4y + 3 ⠀⠀⠀⠀⠀⠀ i
• y = -2x - 3⠀⠀⠀⠀⠀⠀⠀⠀ii

To find;

• The value of xy

${\boxed{\red{\underline{\sf{Solution:}}}}}$

Putting the value of x in ii, we get ;

➝ y = - 2(4y+3) - 3

➝ y = - 8y - 6 - 3

➝ y = - 8y - 9

➝ y + 8y = - 9

➝ 9y = - 9

∴ y = - 1

Putting the value of y in i, we get ;

➝ x = 4y + 3

➝ x = 4(-1) + 3

➝ x = - 4 + 3

∴ x = - 1

Now,

➛ xy = (- 1)(-1)

⛬ xy = 1