Tehtävä 120.
a) [[$x^2+2x+1$]]

b) [[$x^2-2x+1$]]

c) [[$x^2-1$]]

d) [[$9x^2+6x+1$]]

e) [[$9x^2-6x+1$]]

f) [[$9x^2-1$]]

g) [[$4x^2-16xy+16y^2$]]

h) [[$9x^2+12x^3+4x^4$]]

i) [[$4x^4+12x^3+9x^2$]]

j) [[$-x^6+x^5+3x^3-3x^2$]]

Tehtävä 121.
a) [[$9x^2-6xy+y^2+12x+4y+4$]]

b) [[$9x^2+6xy-12x+y^2-4$]]

c) [[$9x^2+6xy+y^2-4$]]

d) [[$ax^5+2ax^4+4x^2+2ax^3+x+6ax^3y^3+ax^3y^2-2ax^3y-\frac{3}{2}ax^3+12xy^3+2xy^2-4xy+9y^5-\frac{23}{4}y^4+\frac{23}{2}y^3+\frac{11}{4}y^2-\frac{1}{2}y+\frac{1}{16}$]]

Tehtävä 122.

a) [[$a^2x^4+4ax^3+6x^2y^3+2ax^2+4x^2+12xy^3+4x+9y^6-\frac{y^4}{4}+7y^3-\frac{y^2}{4}-\frac{3y}{2}+\frac{7}{16}$]]

b) [[$4x^2+16x^3+16x^2$]]

c) [[$64x^{12}+60x^{10}+25x^8$]]

d) [[$x^4-x^2$]]

e) [[$4y^4-9y^2$]]

f) [[$2+2\sqrt(2)x^2+1$]]

g) [[$2x^4-9$]]

Tehtävä 123.
a) [[$(x+y)^2$]]

b) [[$(x-4)^2$]]

c) [[$(2x+1)^2$]]

d) [[$(3x+3^2)$]] tai [[$9(x+1)^2$]]

e) [[$(4x^2+5x)^2$]]

Tehtävä 124.
a) [[$(x-3)(x+3)$]]

b) [[$(x-4y)(x+4y)$]]

c) [[$(2x-3)(2x+3)$]]

d) [[$(x-\sqrt{3})(x+\sqrt{3})$]]

e) [[$(x^2-\sqrt{5})(x^2+\sqrt{5})$]]