Question

2x(x-3)-5(x-3)＝0 2x平方-2√2x-3＝0 求解。。急急急急急急急急！

5/2是5在下还是在上？

Answer 1

2x(x-3)-5(x-3)＝0
(x-3)(2x-5)=0
x=3,x=5/2

2x²-2√2x-3＝0
x²-√2x=3/2
x²-√2x+1/2=1/2+3/2=2
(x-√2/2)²=(±√2)²
x-√2/2=±√2
x=-√2/2，x=3√2/2

Answer 2

2x(x-3)-5(x-3)＝0
（2x-5）（x-3）=0
x=5/2 或 x=3

2x²-2√2x-3=0
（√2 x +1）（√2 x -3）=0
√2 x+1=0 或 √2 x-3 =0
∴x =-√2/2 或 x=3√2/2

Answer 3

解：2x(x-3)-5(x-3)=0
(x-3)(2x-5)=0
x-3=0,2x-5=0
x1=3,x2=5/2,补充说明，5在上，2在下，是2分之5
2x²-2√2x-3=0
(√2x+1)(√2x-3)=0
√2x+1=0,√2x-3=0
x1=-√2/2,x2=3√2/2

Answer 4

2x(x-3)-5(x-3)＝0
(2x-5)(x-3) = 0
x=5/2 或 x=3

2x平方-2√2x-3＝0
x=3/2√2 或 x= - √2/2

Answer 5

2x(x-3)-5(x-3)＝0
（x-3)(2x-5)=0
x-3=0, 2x-5=0
x1=3,x2=5/2

2x平方-2√2x-3＝0
(x√2-3)(x√2+1)=0
x√2-3=0,x√2+1=0
x1=3√2/2,x2=-√2/2

Answer 6

x=9