Question

用配方法解下列方程:2x的平方+3=5x -3x的平方-2x+1=0 急需！！

Answer 1

原方程1为:2x²＋3=5x
2x²－5x＋3=0
x²－5／2 x＋(5／4)²=1／16
(x－5／4)²=1／16
x－5／4=±1／4
x=5／4±1／4
所以x1=3／2 x2=1
原方程2为;﹣3x²－2x＋1=0
3x²＋2x－1=0
x²＋2／3x＋(1／3)²=4／9
(x＋1／3)²=4／9
x＋1／3=±2／3
所以x1= 1／3 x2=﹣1

Answer 2

2x²+3=5x
2x²-5x+3=0
2x²-5x+3=0
2(x²-5x/2 + 25/16) - 1/8 = 0
(x²-5x/2 + 25/16) = 1/16
(x - 5/4)² = 1/16
x - 5/4 = ±1/4
x = 5/4 ±1/4
x1 = 1.5
x2 = 1

-3x²-2x+1=0
3x²+2x-1=0
x²+2x/3 -1/3=0
x²+2x/3 +1/9 -4/9=0
(x+1/3)² = 4/9
x+1/3 = ±2/3
x = -1/3 ± 2/3
x1 = -1
x2 = 1/3