Tính
cau 26 : ket qua x^2-(2y)^2
cau 27 : ket quax^2-1
cau 28 ket qua (x-7)^2
cau 29:a)x^2+6xy+9v^2
b) ( 2x-3y)(2x+3y)
c) 9x^2-6x+1
cau 30: ket qua x^3+3x^2+3x+1
cau 31 : ket qua x^3-x^2+1/3x -1/27
cau 32: ket qua8x^3+12x^2y+6xy^2+y^3
cau 33: a) x^3-3x^2+3x-1
b) x^2+8x+16
c) 3x^2+3x+1+x^3
cau 34 : khai trien ( 5x-1)^3 dc ket qua la
cau 35 rut gon bieu thuc ( a+b)^2- (a-b)^2
cau 36: ( x+3)(x^2-3x+9)
cau 37: dien don thuc vao cho trong : (3x+y)(.............-3xy+y^2) = 27x^3+y^3
cau 38 dang thuc x^3+y^3=9x+y)^3 - 3xy(x+y)
cau39:a) (x+y)(x-y)
b)x^2-2xy+y^2
c) ( x+y)^2
d) ( x+y)9x^2-xy+y^2)
cau 27 : ket quax^2-1
cau 28 ket qua (x-7)^2
cau 29:a)x^2+6xy+9v^2
b) ( 2x-3y)(2x+3y)
c) 9x^2-6x+1
cau 30: ket qua x^3+3x^2+3x+1
cau 31 : ket qua x^3-x^2+1/3x -1/27
cau 32: ket qua8x^3+12x^2y+6xy^2+y^3
cau 33: a) x^3-3x^2+3x-1
b) x^2+8x+16
c) 3x^2+3x+1+x^3
cau 34 : khai trien ( 5x-1)^3 dc ket qua la
cau 35 rut gon bieu thuc ( a+b)^2- (a-b)^2
cau 36: ( x+3)(x^2-3x+9)
cau 37: dien don thuc vao cho trong : (3x+y)(.............-3xy+y^2) = 27x^3+y^3
cau 38 dang thuc x^3+y^3=9x+y)^3 - 3xy(x+y)
cau39:a) (x+y)(x-y)
b)x^2-2xy+y^2
c) ( x+y)^2
d) ( x+y)9x^2-xy+y^2)