Question

Решите пожалуйста.На фотографии.

Answer 1

$2. =a^2-10a+25-a^2+3a+7a-21=4$

3. $a_{1}, a_{2}, a_{3}; b=-5$
$a_{1} * a_{2}- (a_{3}) ^{2} =5; a_{1}=x; a_{2}=x-5; a_{3}=x-10;$
x*(x-5)-(x-10)²=5
 x²-5x-x²+20x-100=5
   15x==105
     x=7
$a_{1}=7; a_{2}=7-5=2; a_{3}=7-10=-3$

4. $a)= \frac{7a^2b}{3c^3} ; b) = \frac{(3m-k)(3m+k)}{7m(3m-k)}= \frac{3m+k}{7m}$