127k views
5 votes
X+4y=11 and 2x+2y=-8 solve by elimination

User Cafedeichi
by
8.0k points

1 Answer

7 votes
Multiply the first equation by -2,and multiply the second equation by 1.−2(x+4y=11)1(2x+2y=−8)Becomes:2x8y=−222x+2y=−8Add these equations to eliminate x:6y=−30Then solve6y=−30for y:6y−6=−30−6(Divide both sides by -6)y=5Now that we've found y let's plug it back in to solve for x.Write down an original equation:x+4y=11Substitute5foryinx+4y=11:x+(4)(5)=11x+20=11(Simplify both sides of the equation)x+20+−20=11+−20(Add -20 to both sides)x=−9Answer:x=9 and y=5
User Duykhoa
by
8.7k points