Phân tích các đa thức sau thành nhân tử (tách một hạng tử thành nhiều hạng tử)
f) x^2-5x-14
i) x^2-7x+10
h) x^2-7x+12
g) x^2+6x+5
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Những câu hỏi liên quan
H9
HT.Phong (9A5)
CTVHS
22 tháng 10 2023
a) \(x^3+4x^2-21x\)
\(=x\left(x^2+4x-21\right)\)
\(=x\left(x^2-3x+7x-21\right)\)
\(=x\left[x\left(x-3\right)+7\left(x-3\right)\right]\)
\(=x\left(x-3\right)\left(x+7\right)\)
b) \(5x^3+6x^2+x\)
\(=x\left(5x^2+6x+1\right)\)
\(=x\left(5x^2+5x+x+1\right)\)
\(=x\left[5x\left(x+1\right)+\left(x+1\right)\right]\)
\(=x\left(x+1\right)\left(5x+1\right)\)
c) \(x^3-7x+6\)
\(=x^3+2x^2-3x-2x^2-4x+6\)
\(=x\left(x^2+2x-3\right)-2\left(x^2+2x-3\right)\)
\(=\left(x-2\right)\left(x^2+2x-3\right)\)
\(=\left(x-2\right)\left(x-1\right)\left(x+3\right)\)
d) \(3x^3+2x-5\)
\(=3x^3+3x^2+5x-3x^2-3x-5\)
\(=x\left(3x^2+3x+5\right)-\left(3x^2+3x+5\right)\)
\(=\left(x-1\right)\left(3x^2+3x+5\right)\)
6 tháng 9 2020
a) \(x^2-5x+6=x^2-2x-3x+6=\left(x-2\right)\left(x-3\right)\)
b)\(3x^2+9x-30=3x^2-6x+15x-30=3\left(x-2\right)\left(x+5\right)\)
c)\(x^2-7x+12=x^2-3x-4x+12=\left(x-3\right)\left(x-4\right)\)
d)\(x^2-7x+10=x^2-2x-5x+10=\left(x-2\right)\left(x-5\right)\)
NN
6 tháng 9 2020
a) \(x^2-5x+6=x^2-2x-3x+6=\left(x^2-2x\right)-\left(3x-6\right)\)
\(=x\left(x-2\right)-3\left(x-2\right)=\left(x-2\right)\left(x-3\right)\)
b) \(3x^2+9x-30=3\left(x^2+3x-10\right)=3\left(x^2-2x+5x-10\right)\)
\(=3\left[\left(x^2-2x\right)+\left(5x-10\right)\right]=3\left[x\left(x-2\right)+5\left(x-2\right)\right]\)
\(=3\left(x-2\right)\left(x+5\right)\)
c) \(x^2-7x+12=x^2-3x-4x+12=\left(x^2-3x\right)-\left(4x-12\right)\)
\(=x\left(x-3\right)-4\left(x-3\right)=\left(x-3\right)\left(x-4\right)\)
d) \(x^2-7x+10=x^2-2x-5x+10=\left(x^2-2x\right)-\left(5x-10\right)\)
\(=x\left(x-2\right)-5\left(x-2\right)=\left(x-2\right)\left(x-5\right)\)
H
21 tháng 8 2021
Phân tích đa thức thành nhân tử(tách hạng tử)
1)x^2+2x-3=x^2-x+3x-3=x(x-1)+3(x-1)=(x-1)(x+3)
2)x^2-5x+6=x^2-2x-3x+6=x(x-2)-3(x-2)=(x-2)(x-3)
3)x^2+7x+12=(x+3)(x+4)
4)x^2-x-12=(x-4)(x+3)
5)3x^2+3x-36=3[(x-3)(x+4)]
6)5x^2-5x-10=5[(x-2)(x+1) ]
7)3x^2-7x-6=(x-3)(3x+2)
8)4x^2+4x-3=4x^2+6x-2x-3=(2x-1)(2x+3)
9)8x^2-2x-3=8x^2+4x-6x-3=(4x-3)(2x+1)
21 tháng 8 2021
1: \(x^2+2x-3=\left(x+3\right)\left(x-1\right)\)
2: \(x^2-5x+6=\left(x-2\right)\left(x-3\right)\)
3: \(x^2+7x^2+12x=4x\left(2x+3\right)\)
4: \(x^2-x-12=\left(x-4\right)\left(x+3\right)\)
5: \(3x^2+3x-36=3\left(x^2+x-12\right)=3\left(x+4\right)\left(x-3\right)\)
6: \(5x^2-5x-10=5\left(x^2-x-2\right)=5\left(x-2\right)\left(x+1\right)\)
18 tháng 6 2016
\(12x^2+7x-12=12x^2-5x+12x-12\)
\(=x\left(12x-5\right)+12\left(x-1\right)\)
Đề sai rồi bạn ời
2 tháng 8 2016
\(12x^2+7x-12=\left(12x^2-9x\right)+\left(16x-12\right)=3x\left(4x-3\right)+4\left(4x-3\right)=\left(3x+4\right)\left(4x-3\right)\)
HB
2
12 tháng 7 2017
a)
\(x^3-7x-6=x^3+1-7x-7\)
= \(\left(x+1\right)\left(x^2-x+1\right)-7\left(x+1\right)\)
= \(\left(x+1\right)\left(x^2-x+1-7\right)\)
= \(\left(x+1\right)\left(x^2-x-6\right)\)
b)
\(x^3-5x^2-14x=x^3+2x^2-7x^2-14x\)
= \(x^2\left(x+2\right)-7x\left(x+2\right)\)
= \(\left(x^2-7x\right)\left(x+2\right)\)
= \(x\left(x-7\right)\left(x+2\right)\)
12 tháng 7 2017
a,x^3 -x-6x-6 = x(x^2 -1)-6(x+1)= x(x-1)(x+1)-6(x+1)=(x+1)(X^2-x-6)=(x+1)(x^2+2x-3x-6)=(x+1)(x(x+2)-3(x+2))=(x+1)(x+2)(x-3)
b,x(x^2-5x-14)=x(x^2+2x-7x-14)=x(x(x+2)-7(x+2))=x(x+2)(x-7)
2 tháng 7 2021
a) x2 + 5x + 6
= x2 + 2x + 3x + 6
= (x2 + 2x) + (3x + 6)
= x(x + 2) + 3 (x + 2)
= (x + 2) (x + 3)
b) x2 + 6x + 8
= x2 + 2x + 4x + 8
= (x2 + 2x) + (4x + 8)
= x(x + 2) + 4(x + 2)
= (x + 2)(x + 4)
c) x2 - 5x - 14
= x2 + 2x - 7x - 14
= (x2 + 2x) - (7x + 14)
= x(x + 2) - 7(x + 2)
= (x + 2)(x - 7)
d) x2 - 9x + 18
= x2 - 3x - 6x + 18
= (x2 - 3x) - (6x + 18)
= x(x - 3) - 6 (x - 3)
= (x - 3)(x - 6)
e) x2 - 7x + 12
= x2 -3x - 4x + 12
= (x2 - 3x) - (4x + 12)
= x(x - 3) - 4(x - 3)
= (x - 3)(x - 4)
f) 3x2 + 9x - 30
= 3(x2 + 3x - 10)
= 3\(\left[\left(x^2+5x-2x-10\right)\right]\)
= 3\(\left[\left(x^2+5x\right)-\left(2x-10\right)\right]\)
= 3\(\left[x\left(x+5\right)-2\left(x+5\right)\right]\)
= 3(x + 5)(x - 2)
Chuc ban hoc tot
2 tháng 7 2021
a) \(x^2+5x+6=\left(x+2\right)\left(x+3\right)\)
b) \(x^2+6x+8=\left(x+2\right)\left(x+4\right)\)
c) \(x^2-5x-14=\left(x-7\right)\left(x+2\right)\)
d) \(x^2-9x+18=\left(x-3\right)\left(x-6\right)\)
e) \(x^2-7x+12=\left(x-3\right)\left(x-4\right)\)
f) \(3x^2+9x-30=3\left(x^2+3x-10\right)=3\left(x+5\right)\left(x-2\right)\)
NT
30 tháng 10 2017
a) \(=x^2-2x-4x+8\)
\(=x\left(x-2\right)-4\left(x-2\right)\)
\(=\left(x-2\right)\left(x-4\right)\)
c) \(=x^3-x-6x-6\)
\(=x\left(x^2-1\right)-6\left(x+1\right)\)
\(=x\left(x+1\right)\left(x-1\right)-6\left(x+1\right)\)
\(=x\left(x+1\right)\left(x-1-6\right)\)
\(=x\left(x+1\right)\left(x-7\right)\)
f)\(x^2-5x-14=x^2-7x+2x-14=x\left(x-7\right)+2\left(x-7\right)=\left(x-7\right)\left(x+2\right)\)
i)\(x^2-7x+10=x^2-2x-5x+10=x\left(x-2\right)-5\left(x-2\right)=\left(x-5\right)\left(x-2\right)\)
h)\(x^2-7x+12=x^2-3x-4x+12=x\left(x-3\right)-4\left(x-3\right)=\left(x-4\right)\left(x-3\right)\)
g)\(x^2+6x+5=x^2+x+5x+5=x\left(x+1\right)+5\left(x+1\right)=\left(x+1\right)\left(x+5\right)\)
f)\(x^2-5x-14=x^2-7x+2x-14\)
\(=\left(x+2\right)\left(x-7\right)\)
i)\(x^2-7x+10=x^2-5x-2x+10\)
\(=\left(x-2\right)\left(x-5\right)\)
h)\(x^2-7x+12=x^2-4x-3x+12\)
\(=\left(x-3\right)\left(x-4\right)\)
g)\(x^2+6x+5=x^2+x+5x+5\)
\(=\left(x+5\right)\left(x+1\right)\)