How do I solve and check this system of equations?

solve and check algebraically

2x^2-4x=y+12x24x=y+1
x+y=1x+y=1

1 Answer

(x,y)=(-1/2,3/2)(x,y)=(12,32)
and
(x,y)=(2,-1) form solutions(x,y)=(2,1)formsolutions

Explanation:

Given:
2x^2-4x=y+12x24x=y+1
x+y=1x+y=1
y=1-xy=1x
2x^2-4x=1-x+12x24x=1x+1
2x^2-4x=2-x2x24x=2x
2x^2-4x+x-2=02x24x+x2=0
2x^2-3x-2=02x23x2=0
2x^2-4x+x-2=02x24x+x2=0
2x(x-2)+1(x-2)=02x(x2)+1(x2)=0
(2x+1)(x-2)=0(2x+1)(x2)=0

2x+1=02x+1=0
2x=-12x=1
x=-1/2x=12
y=1-xy=1x
y=1-(-1/2)y=1(12)
1+1/21+12
y=3/2y=32
Check:
2x^2-4x=y+12x24x=y+1----(1)
2(-1/2)^2-4xx(-1/2)=3/2+12(12)24×(12)=32+1
2xx1/4+4xx1/2=3/2+2/22×14+4×12=32+22
1/2+4/2=3/2+2/212+42=32+22
(1+4)/2=(3+2)/21+42=3+22
5/2=5/252=52
lhs=rhs
x+y=1x+y=1-----(2)
-1/2+3/2=112+32=1
(-1+3)/2=11+32=1
2/2=122=1
1=11=1
lhs=rhs

x-2=0x2=0
x=2x=2
y=1-xy=1x
y=1-2y=12
y=-1y=1
Check:
2(2)^2-4(2)=-1+12(2)24(2)=1+1-----(1)
2(4)-8=02(4)8=0
8-8=088=0
0=00=0
lhs=rhs
x+y=1x+y=1-----(2)
2+(-1)=12+(1)=1
2-1=121=1
1=11=1
lhs=rhs

Thus,
(x,y)=(-1/2,3/2)(x,y)=(12,32)
and
(x,y)=(2,-1) form solutions(x,y)=(2,1)formsolutions