<span> (an) арифметическая прогрессия;
1) a1 =11; d =3 найдите a11.
a</span>₁₁ = a₁ + 10d = 11 + 10*3 = 41<span>
2) a1=137; d=-7 найдите S10.
S</span>₁₀ = (2a₁ + 9d)*10/2 = ( 2*137 +9*(-7))*5 = 1055<span>
3) a13=-27, a15=-13 найдите a14
a</span>₁₄ = (a₁₃ + a₁₅)/2 = (-27 - 13)/2 = -20<span>
4) a43=-208, d=-7 найдите a1
a</span>₄₃ = a₁ + 42d
<span>-208 = a</span>₁ +42*(-7)
<span>-208 = a</span>₁ - 294
<span>a</span>₁ = -208 + 294= 86<span>
5) a1=35 , a15=-21 найдите d
a</span>₁₅ = a₁ + 14d
-21 = 35 + 14d
14d = -56
d = - 4
7/36-36^2-7/36+
0-36^2=
-36^2 или -1296
1) 3a(a-b)+b(20-b)= 3a^2 - 3ab + 20b - b^2 = 3a^2 -b^2 -3ab + 29b
2) -4x^3 (x^2 -3x+2)= -4x^5 + 12x^4 - 8x^3
3) (5c-4)^2 = 5c^2 - 4^2 = 5c^2 - 16
4) 2x^2 - 0,5x+6 при x=4
2•4^2 - 0,5•4+6
1) x-16<span><0
x</span><span><16
2) 28x+4</span><span>>0
28x</span><span>>-4
x</span><span>>-1/7
3) 31x+63</span><span>>36x+23
31x-36x</span><span>>23-63
-5x</span><span>>-40
x</span><span>>8</span>