Question

solve the simultaneous equation using elimination method
(iv) 4x + 4y = -4, x + 7y = -19​

Answer 1

Answer:

$\huge\boxed{\left\{\begin{array}{ccc}x=2\\y=-3\end{array}\right }$

Step-by-step explanation:

$\left\{\begin{array}{ccc}4x+4y=-4&|\text{divide both sides by (-4)}\\x+7y=-19\end{array}\right\\\\\underline{+\left\{\begin{array}{ccc}-x-y=1\\x+7y=-19\end{array}\right}\qquad|\text{add both sides of the equations}\\.\qquad6y=-18\qquad|\text{divide both sides by 6}\\.\qquad y=-3\\\\\text{substitute it to the first equation}\\\\-x-(-3)=1\\-x+3=1\qquad|\text{subtract 3 from both sides}\\-x=-2\qquad|\text{change the signs}\\x=2$

Answer 2

Answer:

Question :-

Solve the simultaneous equation using elimination method

(iv) 4x + 4y = -4 , x + 7y = - 19

Answer :-

➠ 4x + 4y = - 4. . . .(1)

➠ x + 7y = - 19 . . . .(2)

Multiply (1) by 7 (2) by 4 we get,

28x + 28y = - 28

4x + 28y = - 76

(-) (-) (+)

___________________

24x = 48

x = 48/2

x = 2

Then, x = 2

➻ 4x + 4y = - 4

➻ 4(2) + 4y = - 4

➻ 8 + 4y = - 4

➻ 4y = - 4 - 8

➻ 4y = - 12

➻ y = - 12/4

➻ y = - 3

Hence, the value of x = 2, y = - 3.