b) (94,5^2-30,5^2): ((69^3+29^3):98-69*29)=(94.5+30.5)(94.5-30.5)/(69:2-69*29+29^2-69*29)= 125*64/(69-29)^2=5^3*4^3/40^2=20^3/40^2=8000/1600=5
16a^2+8a+1/12a+3=(4a+1)/3(4a+1)=1/3
Из равенства а+2*b=4 находим a=4-2b, тогда:
а=(4-2b)=64-96*b+48*b-8*b,
a+8*b=64-96*b+48*b,
64-24*a*b=64-24*b*(4-2*b)=64-96*b+48*b
Равенство доказано.
1) a + 2b = 4;
(a + 2b) = 4;
a + 4ab + 4b = 16;
2) a + (2b) = 64 — 24ab;
(a + 2b)*(a — 2ab + 4b) = 64 — 24ab;
4(a — 2ab + 4b) = 64 — 24ab;
a — 2ab + 4b = 16 — 6ab;
a + 4ab + 4b = 16;
16 = 16