-7X<span>²-46x+21=0 | *(-1)
</span>7X²+46x-21=0
X1,2=-46±<span>√2116+588/14.
</span>Х1 = -46-52 / 14 = -98/14 = -7
Х2 = -46+52 / 14 = 6/14 = 3/7
Ответ: -7;3/7
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144.
1) (0.25a⁻⁴ y⁻³)² * (a⁻³/(4y²))⁻³ =((1/4)² a⁻⁸ y⁻⁶) * (a⁹ *4³ *y⁶) =
=4⁻²⁺³ a⁻⁸⁺⁹ y⁻⁶⁺⁶ =4a
2) ((x⁻³ y⁴)/9)⁻² * (3/(x⁻² y³))⁻³ = (x⁶ y⁻⁸ * 3⁴) * (3⁻³ x⁻⁶ y⁹) =
=3⁴⁻³ x⁶⁻⁶ y⁻⁸⁺⁹ = 3y
3) (m⁻⁴/(10n⁵ k²))⁻² : (5m² n³ k)³ = (m⁸ * 10² * n¹⁰ k⁴) * (5⁻³ m⁻⁶ n⁻⁹ k⁻³)=
= 2² * 5² * 5⁻³ m⁸⁻⁶ n¹⁰⁻⁹ k⁴⁻³ =4 * 5⁻¹ m² n k = 0.8 m² n k
4) ((9c⁵)/(a³b⁻²))⁻² : ((a²b⁻³)/(6c⁴))³ = (9⁻² c⁻¹⁰ a⁶ b⁻⁴) * (6³ c¹² a⁻⁶ b⁹)=
=3⁻⁴ *2³ * 3³ c⁻¹⁰⁺¹² a⁶⁻⁶ b⁻⁴⁺⁹ = 2³ * 3⁻¹ c² b⁵ = <u>8 c² b⁵</u>
3
A) a²+8a+16
б) a²-25
в) (2х)³-3*(2х)²*3+3*2х*3²-3³=8х³-12х²+54х-27
г)х³+8