Question

Разложить на множетели. х^2-x-72 15u^2+u-2 49c^2-46c+9 x^4-13x^2+36 a^2+10ab+9b^2

Answer 1

$x^2-x-72=(x-9)(x+8)$

$15u^2+u-2=0;\\D=1-4*15*(-2)=121=11^2;\\u_1=\frac{-1+11}{2*15}=\frac{10}{30}=\frac{1}{3};\\u_2=\frac{-1-11}{2*15}=\frac{-12}{30}=-\frac{2}{5};$

$15u^2+u-2=15(u-\frac{1}{3})(u-(-\frac{2}{5}))=(3u-1)(5u+2)$

$49c^2-46c+9=0;\\D=(-46)^2-4*49*9=352=16*22;c_1=\frac{-(-46)+4\sqrt{22})}{2*49}=\frac{23+2\sqrt{22}}{49};\\c_2=\frac{-(-46)-4\sqrt{22}}{2*49}=\frac{23-2\sqrt{22}}{49};$

$49c^2-46c+9=49*(x-\frac{23-2\sqrt{22}}{49})(x+\frac{23+2\sqrt{22}}{49})$

$x^4-13x^2+36=(x^2-4)(x^2-9)=(x-2)(x+2)(x-3)(x+3)$

$a^2+10ab+9b^2=(a+b)(a+9b)$

Answer 2

1)=(х-9)(х+8)

2)=(х+0,4)(х-0,3333)

3)

4)х=+-3,х=+-2

5)=(а+б)(а+9б)