解下列各方程

1.
3x(x+1)=2(1-x)
3x^2+3x=2-2x
3x^2+5x-2=0
(3x-1)(x+2)=0
(3x-1)=0 or (x+2)=0
x=1/3 or -2

2.
The question is missing the ‘=’ sign……
If the question is like this:
A)y=x^2-x-1
2x=y-2

2x=(x^2-x-1)-2
2x=x^2-x-3
x^2-3x-3=0
By using the calculator with the formula for solving quadratic equation,
x=3.79 or -0.791(correct to 3 sig. fig.)

B)y+ x^2=x-1
2x = y-2

y+ x^2=x-1
y=x-1-x^2

2x=( x-1-x^2)-2
2x=x-3-x^2
x^2+x+3=0
By using the calculator with the formula for solving quadratic equation,
x is not a real number.

C)y+ x^2-x=1
2x = y-2

y+ x^2-x=1
y=1+x-x^2

2x=(1+x-x^2)-2
2x=x-x^2-1
x^2+x+1=0
By using the calculator with the formula for solving quadratic equation,
x is not a real number.

I hope I can help you(If the question is not like these(A/B/C), please let me know)

第2題出錯題= =