1)(8x+1)(2x-3)-(4x-2)^2=1 2)x^3-144x=0 3)x^4-10x^2+9=0

Question

1)(8x+1)(2x-3)-(4x-2)^2=1
2)x^3-144x=0
3)x^4-10x^2+9=0

Answer 1

1) (8х + 1)(2х - 3) - (4х - 2)^2 - 1 = 0
16х^2 - 24x + 2x - 3 - (16x^2 - 16x + 4) - 1 = 0
16x^2 - 24x + 2x - 3 - 16x^2 + 16x - 4 - 1 = 0
10x - 8 = 0
10x = 8
x = 0,8

2) x^3 - 144x = 0
x (x^2 - 144) = 0
а) x = 0;
б) x^2 = 144
x = 12; -12

3) x^4 - 10x^2 + 9 = 0
x^2 = t
t^2 - 10t + 9 = 0
D1 = 25 - 9 = 16; корень из D1 = 4
t1 = 5 + 4 = 9; t2 = 5 - 4 = 1
a) x^2 = 9
x = 3; -3
б) x^2 = 1
x = 1; -1

Comments

Спасибо, по какой формуле решали 1 пример

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квадрат разности двух выражений

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(a - b)^2 = a^2 - 2ab + b^2