1) (46 +14+25)-8*(3*3)=85-8*9=85-72=13
2) Легко (Без упрощения можно) 32/4+4*2*2=24
3) 41+19+42/6=77+7=84
4)358-9-9*0*3*8=358-9-0=349
<span> а> 0,
81+а >81,
7-а< 7,
а< 10+а.</span>
648. б) b1 = 500, q = 1/5
S(5) = b1*(1 - q^5) / (1 - q) = 500*(1 - 1/3125) / (1 - 1/5) =
= 500*(3124/3125) / (4/5) = 500*3124/3125*5/4 = 624,8
649. а) b1 = 3, b2 = -6, q = b2/b1 = -6/3 = -2
S(6) = 3*((-2)^6 - 1)/(-2-1) = 3*(64 - 1)/(-3) = -63
в) b1 = -32, b2 = -16, q = b2/b1 = (-16)/(-32) = 1/2
S(6) = -32*(1 - (1/2)^6) / (1 - 1/2) = -32*(1 - 1/64) / (1/2) =
= -32*2*63/64 = -63
650. а) c1 = -4, q = 3
S(9) = -4*(3^9 - 1)/(3 - 1) = -4*(19683 - 1)/2 = -2*19682 = -39364
4xy-x^2+16y^2-4xy=2t^2+16t-t^2+12t-36
16y^2-x^2=t^2+28t-36
16y^2-x^2-t^2-28t+36=0
^2-------в квадрате(двойка сверху)