利用平方差公式解方程:
1. 9x^2-121=0
(3x+11)(3x-11)=0
x1=-11/3 , x2=11/3
2. 4(x-3)^2-169=0
[2(x-3)+13][2(x-3)-13]=0
(2x+7)(2x-19)=0
x1=-7/2 , x2=19/2
3. 18(a-5)^2-169=2(a-5)^2-25
16(a-5)^2-144=0
[4(a-5)+12][4(a-5)-12]=0
(4a-8)(4a-32)=0
a1=2 , a2=8
4. 4(p-√3)^2-48=0
[2(p-√3)+4√3][2(p-√3)-4√3]=0
(2p+2√3)(2p-6√3)=0
p1=-√3 , p2=3√3
利用求根公式解方程:
1. x^2-6x+6=0
b^2-4ac=(-6)^2 - 4×1×6=12
x=[-b ± √(b^2-4ac)]/2a =3 ± √3
2. y^2+12y-62=0
b^2-4ac=12^2 - 4×1×(-62)=392
y=[-b ± √(b^2-4ac)]/2a = -6 ± 7√2
3. x^2-5x-2=0
b^2-4ac=(-5)^2 - 4×1×(-2)=33
x=[-b ± √(b^2-4ac)]/2a = (5 ± √33)/2
4. x^2-11x+5=0
b^2-4ac=(-11)^2 - 4×1×5=101
x=[-b ± √(b^2-4ac)]/2a = (11 ± √101)/2
利用十字相乘法解方程:
1. x^2-4x+3=0
(x-1)(x-3)=0
x1=1 , x2=3
2. 3y^2+5y-2=0
(y+2)(3y-1)=0
y1=-2 , y2=1/3
1. x^2-8x+12=0
(x-2)(x-6)=0
x1=2 , x2=6
2. x^2-6x-16=0
(x-8)(x+2)=0
x1=8 , x2=-2
3. a^2-29a-30=0
(a-30)(a+1)=0
a1=30 , a2=-1
利用完全平方公式解方程:
4. m^2-38m+361=0
(m-19)^2=0
m1=m2=19