a: =x^2+7x+49/4-61/4
\(=\left(x+\dfrac{7}{2}\right)^2-\dfrac{61}{4}\)
\(=\left(x+\dfrac{7-\sqrt{61}}{2}\right)\left(x+\dfrac{7+\sqrt{61}}{2}\right)\)
b: \(=9x^2+2\cdot3x\cdot\dfrac{1}{6}+\dfrac{1}{36}+\dfrac{35}{36}\)
\(=\left(3x+\dfrac{1}{6}\right)^2+\dfrac{35}{36}\)
tìm x
a, \(x^2-4x+\dfrac{1}{4}\)
b, \(8x^2-25\)
c, \(x^2+7x=8\)
d, \(x^3-3x=-27+9x\)
e, x(x-3)-7x=-21
f, \(x^3-2x^2+x-2=0\)
g, \(x^2-4x=-4\)
h, \(x^3-x^2+x=-1\)
giải các phương trình
a) (3x-2)(3x-1) = (3x+1)2
b) (4x-1)(x+1) = (2x-3)2
c) (5x+1)2 = (7x-3)(7x+2)
d) (4-3x)(4+3x)=(9x-3)(1-x)
e) x(x+1)(x+2)(x+3)=24
g) (7x - 2)2= (7x-3)(7x+2)
tính nghiệm x) 1 mũ 2 -9x+8 2)3x mũ 2 -7x+4 3)2x mũ 2+5x-7 4) 3x mũ 2-9x+6 5)x mũ 2 +2x-3
bài 1 : Rút gọn biểu thức
a) 3x.(x-2)-5x(1-x)-8(x^2-3)
b) (7x-3) (2x+1) - (5x-2) (x+4)-9x^2 + 17x
Giải phương trình:
a) x+1/x-2 + x-1/x+2 = 2(x^2+2)/x^2-4
b) 2x+1/x^2-5x+4 + 5/x-1 = 2/x-4
c) 2x^2/x^3-8 + x+1/x^2+7x+12 +1/x^2+9x+20 + 1/x^2+11x+30 = 1/15
d) x+4/2x^2-5x+2 + x+1/2x^2-7x+3 = 2x+5/2x^2-7x+3
tìm x
a) x^3-9x+7x^2-63=0
b) x^3-6x^2+9x=0
Bài 1:
a) Max A = (3x^2 + 9x +3) / (x^2 +x +1)
b) Min B = ( 7x^2 +21) / (x^2 + x +2)
phan tích đa thưc thành nhân tử
a) x^2+10x+21
b) x^3-7x+6
c) x^3-7x+6
d) x^3+5x^2+8x+4
e) x^3-9x^2+6x
g) (x+2)(x+3)(x+4)(x+5)-24
h) x^4+6x^3+7x^2-6x+1
A)9x-2(x+3)=3x+1
B)\(\dfrac{5}{x-3}\)-\(\dfrac{4}{x+3}\)=\(\dfrac{x-13}{x^2-9}\)
C)7x+8≥3(x-1)
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