Question

СРОЧНО ПОМОГИТЕ С АЛГЕБРОЙ 7 КЛАСС!!!!! даю 20 баллов ​

Answer 1

1. 1)

$(3k - t)^{3} = 27k^{3} - 3 \times 9k^{2} \times t + 3 \times 3k \times t^{2} - t^{3} = 27k^{3} - 27k^{2} t + 9kt^{2} - t^{3}$

2)

$(0.5m^{2} + n^{4} )^{3} = 0.125m^{6} + 3 \times 0.25m^{4} \times n^{4} + 3 \times 0.5m^{2} \times n^{8} + n^{12} = 0.125m^{6} + 0.75m^{4}n^{4} + 1.5m^{2} n^{8} + n^{12}$

3.

$(5a - 4b)^{3} - (5a + 4b)^{3} = - 8b(75a^{2} + 16b^{2})$

$- 8 \times 2(75 \times - 1^{2} + 16 \times 2^{2} ) = 176$

4.

$(x - 3)^{3} - x^{2} (x - 9) - 27 = 0$

$x^{3} - 9x^{2} + 27x - 27 - x^{3} + 9x^{2} - 27 = 0$

$27x - 54 = 0$

$27x = 54$

$x = 2$