16с^2-25d^2 = (4c - 5d)(4c + 5d);
b^2-49a^2 = (b - 7a)(b + 7a);
144a^2b^2-289 = (12ab - 17)(12ab + 17);
c^2-100b^2 = (c - 10b)(c + 10b);
a^2b^2c^2-225 = (abc - 15)(abc + 15);
49a^2c^2-196 = 49•(a^2c^2 - 4) = 49•(ac - 2)(ac + 2);
x^8-y^8 = (x^4 - y^4)(x^4 + y^4) = (x^2 - y^2)(x^2 + y^2)(x^4 + y^4) = (x - y)(x + y)(x^2 + y^2)(x^4 + y^4);
256-81a^4 = (16 - 9a^2)(16 + 9a^2) = (4 - 3a)(4 + 3a)(16 + 9a^2);
625-c^4 = (25 - c^2)(25 + c^2) = (5 - c)(5 + c)(25 + c^2);
Если нет описки в условии, то
29d^2c^2x^2-196 = (√29dcx - 14)(√29dcx + 14);
144a^2-361b^2 = (12a - 19b)(12a + 19b);
36x^2y^2-121 = (6xy - 11)(6xy + 11);
m^2n^2-64 = (mn - 8)(mn + 8);
х = 3/4-7/12
х = 9/12-7/12
х = 2/12 = 1/6
2)x-1/6=1/9
х = 1/9+1/6
х = 2/18+3/18
х = 5/18
3)x-3/5=3/8
х = 3/8+3/5
х = 15/40+24/40
х = 39/40
4)x+5/24=7/12
х = 7/12-5/24
х = 14/24-5/24
х = 9/24 = 3/8
5)y+2/7=1/3
у = 1/3-2/7
у = 7/21-6/21
у = 1/21
6)x-1/6=7/9
х = 7/9+1/6
х = 14/18+3/18
х = 17/18
7)y-3/8=5/32
у =5/32+3/8
у = 5/32+12/32
у = 17/32
8)y+2/5=1/2
у = 1/2-2/5
у = 5/10-4/10
у = 1/10 = 0.1