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29 tháng 8 2018

a, b, c, dung hang dang thuc A2-B2 =9A-B) (A+B)

d)  a4 - 16 =(a2)2  -42=  (a2-4) (a2+4)  =(a-2)(a+2) (a2+4)

29 tháng 8 2018

\(a..9-4x^2=3^2-\left(2x\right)^2=\left(3-2x\right)\left(3+2x\right)\)

\(b..16x^2-25=\left(4x\right)^2-5^2=\left(4x-5\right)\left(4x+5\right)\)

\(c..a^4-16=\left(a^2\right)^2-4^2=\left(a^2-4\right)\left(a^2+4\right)\)

\(d..\left(a+b\right)^2-1=\left(a+b\right)^2-1^2=\left(a+b-1\right)\left(a+b+1\right)\)

k mik đi

a,16x2-9

=42x2-32

=(4x-3)(4x+3) HĐT thứ 3

b,9a2-25b2

=32a2-52b2

=(3a-5b)(3a+5b) HĐT thứ 3

c,81-y4

=32.32-y2.y2

=(32-y2)

=(3-y)(3+y) HĐT thứ 3

d,(2x+y)2-1

=(2x+y-1)(2x+y-1) HĐT thứ 3

e,(x+y+z)2-(x-y-z)2

cái này là HĐT thứ 8 mở rộng bạn lên mạng tìm nha

7 tháng 9 2019

a) \(16x^2-9=\left(4x\right)^2-3^2=\left(4x-3\right).\left(4x+3\right)\)

b) \(9a^2-25b^4=\left(3a\right)^2-\left(5b^2\right)^2=\left(3a-5b^2\right).\left(3a+5b^2\right)\)

c) \(81-y^4=9^2-\left(y^2\right)^2=\left(9-y^2\right).\left(9+y^2\right)\)

d)\(\left(2x+y\right)^2-1=\left(2x+y\right)^2-1^2=\left(2x+y-1\right).\left(2x+y+1\right)\)

7 tháng 9 2019

a) 16x2−9

=(4x-3)(4x+3)

b) 9a2−25b4

=(3a-5b2)(3a+5b2)

c) 81−y4

=(9-y2)(9+y2)

d) (2x+y)2−1

=(2x+y-1)(2x+y+1)

e) (x+y+z)2−(x−y−z)2

=(x+y+z-x+y+z)(x+y+z+x-y-z)

=(2y+2z)2x

=4x(y+z)

23: \(=\left(2a-b\right)^2-\left(2a-2b\right)^2\)

\(=\left(2a-b-2a+2b\right)\left(2a-b+2a-2b\right)\)

\(=b\left(4a-3b\right)\)

24: \(=\left(3a+3b\right)^2-\left(2a-4b\right)^2\)

\(=\left(3a+3b-2a+4b\right)\left(3a+3b+2a-4b\right)\)

\(=\left(a+7b\right)\left(5a-b\right)\)

25: \(=\left(4a-2b\right)^2-\left(4a-4b\right)^2\)

\(=\left(4a-2b-4a+4b\right)\left(4a-2b+4a-4b\right)\)

\(=2b\left(8a-6b\right)\)

=4b(4a-3b)

4 tháng 8 2018

a) \(16-x^2\)

\(=\left(4\right)^2-x^2\)

\(=\left(4-x\right)\left(4+x\right)\)

b) \(4x^2-9y^2\)

\(=\left(2x\right)^2-\left(3y\right)^2\)

\(=\left(2x-3y\right)\left(2x+3y\right)\)

c) \(a^4-25\)

\(=\left(a^2\right)^2-5^2\)

\(=\left(a^2-5\right)\left(a^2+5\right)\)

d) \(\left(a+b\right)^2-4\)

\(=\left(a+b\right)^2-2^2\)

\(=\left(a+b-2\right)\left(a+b+2\right)\)

4 tháng 8 2018

a. \(16-x^2=4^2-x^2=\left(4-x\right)\left(4+x\right)\)

b. \(4x^2-9y^2=\left(2x\right)^2-\left(3y\right)^2=\left(2x-3y\right)\left(2x+3y\right)\)

c. \(a^4-25=\left(a^2\right)^2-5^2=\left(a^2-5\right)\left(a^2+5\right)\)

d. \(\left(a+b\right)^2-4=\left(a+b\right)^2-2^2=\left(a+b-2\right)\left(a+b+2\right)\)TK MIK NHAvui

19 tháng 7 2018

\(16-x^2=4^2-x^2=\left(4-x\right)\left(4+x\right)\)

\(4x^2-9=\left(2x\right)^2-3^2=\left(2x-3\right)\left(2x+3\right)\)

\(a^4-25=\left(a^2\right)^2-5^2=\left(a^2-5\right)\left(a^2+5\right)\)

\(\left(a+b\right)^2-1=\left(a+b\right)^2-1^2=\left(a+b-1\right)\left(a+b-1\right)\)

\(\left(a+b\right)^2-\left(m-n\right)^2=\left(a+b-m+n\right)\left(a+b+m-n\right)\)

\(x^3-27=x^3-3^3=\left(x-3\right)\left(x^2+3x+3^2\right)\)

\(64x^3+\frac{1}{27}=\left(4x\right)^3+\left(\frac{1}{3}\right)^3=\left(4x+\frac{1}{3}\right)\left(16x^2+\frac{4}{3}x+\frac{1}{9}\right)\)

Tham khảo~

19 tháng 7 2018

\(16-x^2=4^2-x^2=\left(4-x\right)\left(4+x\right)\)

\(4x^2-9=\left(2x\right)^2-3^2=\left(2x+3\right)\left(2x-3\right)\)

\(a^4-25=\left(a^2\right)^2-5^2=\left(a^2+5\right)\left(a^2-5\right)\)

\(\left(a+b\right)^2-1=\left(a+b+1\right)\left(a+b-1\right)\)

\(\left(a+b\right)^2-\left(m-n\right)^2=\left(a+b+m-n\right)\left(a+b-m+n\right)\)

\(x^3-27=x^3-3^3=\left(x-3\right)\left(x^2+3x+9\right)\)

\(64x^3+\frac{1}{27}=\left(4x\right)^3+\left(\frac{1}{3}\right)^3=\left(4x+\frac{1}{3}\right)\left(16x^2-\frac{4}{3}x+\frac{1}{9}\right)\)

19 tháng 1 2020

a) \(12x-9-4x^2\)

\(=-\left(4x^2-12x+9\right)\)

\(=-\left(2x-3\right)^2\)

b)\(1-9x+27x^2-27x^3\)

\(=\left(1-3x\right)^{^3}\)

c)\(\frac{x^2}{4}+2xy+4y^2-25\)

\(=\left(\frac{x}{2}+2y\right)^2-5^2\)

\(=\left(\frac{x}{2}+2y-5\right)\left(\frac{x}{2}+2y+5\right)\)

d)\(\left(x^2-4x\right)^2-8\left(x^2-4x\right)+15\)

\(=\left(x^2-4x\right)^2-3\left(x^2-4x\right)-5\left(x^2-4x\right)+15\)

\(=\left(x^2-4x\right)\left(x^2-4x-3\right)-5\left(x^2-4x-3\right)\)

\(=\left(x^2-4x-5\right)\left(x^2-4x-3\right)\)

\(=\left(x^2+x-5x-5\right)\left(x^2-4x-3\right)\)

\(=\left[x\left(x+1\right)-5\left(x+1\right)\right]\left(x^2-4x-3\right)\)

\(=\left(x-5\right)\left(x+1\right)\left(x^2-4x-3\right)\)

Chúc bạn học tốt !

15 tháng 8 2018

a , \(16x^2+8x+1=\left(4x\right)^2+2.4x.1+1^2=\left(4x+1\right)^2\)

b , \(x^2-x+\dfrac{1}{4}=x^2-2.x.\dfrac{1}{2}+\left(\dfrac{1}{2}\right)^2=\left(x-\dfrac{1}{2}\right)^2\)

15 tháng 8 2018

a,(4x+1)2 e,\(\left(\dfrac{3}{2}x-\dfrac{2}{5}\right)^2\)

b,(x-\(\dfrac{1}{2}\))2 g,\(\left(xy+1\right)^2\)

c,(\(x+\dfrac{3}{2}\))2 h,\(\left(x+5\right)^2\)

d,\(\left(x-\dfrac{5}{4}\right)^2\) i,\(-\left(x-6\right)^2\)

k,\(-\left(2x+3\right)^2\)

10 tháng 10 2018

a) 9  -(x-y)2

= 32 - (x-y)2

= (3-x+y).(3+x-y)

b) (x2 +4)2 - 16x2

= (x2+4)2 - (4x)2

= (x2 + 4 -4x).(x2 + 4 +4x)

10 tháng 10 2018

      \(9-\left(x-y\right)^2\)

\(=3^2-\left(x-y\right)^2\)

\(=\left(3-x+y\right)\left(3+x-y\right)\)

      \(\left(x^2+4\right)^2-16x^2\)

\(=\left(x^2+4\right)^2-\left(4x\right)^2\)

\(=\left(x^2-4x+4\right)\left(x^2+4x+4\right)\)

\(=\left(x-2\right)^2\left(x+2\right)^2\)