[tex]\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[/tex]
Answer:
[tex]\huge\boxed{\left\{\begin{array}{ccc}x=2\\y=-3\end{array}\right }[/tex]
Step-by-step explanation:
[tex]\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[/tex]
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.