2x + 6 = ( x - 3 )”,
x” - 6x + 9 = 2x + 6,
x” - 8x + 3 = 0,
x” - 8x + 16 - 13 = 0,
x” - 2(4x) + 4” - 13 = 0,
( x - 4 )” - ( √13 )” = 0,
( x - 4 - √13 )( x - 4 + √13 ) = 0,
解方程得,
x1 = 4 + √13,
x2 = 4 - √13,
解:2x+6=(x-3)
x=-3-6=-9
∴ x=-9
2(X+3)=(X+3)-6
X+3=-6
X=-9