Solve the system of equations by the elimination method.
-$- 0.8 x + 0.4 y = 4.8$ $0.1 x - 0.1 y = - 0.7$
A) $( - 50,20 )$
B) $( - 0.5,0.2 )$
C) $( - 5,2 )$
D) $( 2 , - 5 )$

Question

Quizplus · Accepted Answer

Multiply the second equation by 4 to eliminate y:
$$-0.8x+0.4y=4.8$$
$$0.4x-0.4y=-2.8$$
Adding the two equations together eliminates y:
$$-0.4x=2$$
$$x=-5$$
Substitute x=-5 back into any of the original equations to solve for y:
$$-0.8x+0.4y=4.8$$
$$-0.8(-5)+0.4y=4.8$$
$$4+0.4y=4.8$$
$$0.4y=0.8$$
$$y=2$$
Therefore, the solution is (x,y)=(-5,2) which matches choice C.

Solve the System of Equations by the Elimination Method −0.8x+0.4y=4.8- 0.8 x + 0.4 y = 4.8−0.8x+0.4y=4.8

Solve the System of Equations by the Elimination Method $- 0.8 x + 0.4 y = 4.8$