Упр.1.44 ГДЗ Дорофеев Суворова 7 класс (Алгебра)

а) при а = 1/6; б) при а = -0,1.

а) При $$a=\frac{1}{6}$$:

$$9a^2=9\cdot\left(\frac{1}{6}\right)^2=9\cdot\frac{1}{36}=\frac{1}{4}$$
$$\left(9a\right)^2=\left(9\cdot\frac{1}{6}\right)^2=\left(\frac{3}{2}\right)^2=\frac{9}{4}$$
$$-9a^2=-9\cdot\left(\frac{1}{6}\right)^2=-9\cdot\frac{1}{36}=-\frac{1}{4}$$
$$\left(-9a\right)^2=\left(-9\cdot\frac{1}{6}\right)^2=\left(-\frac{3}{2}\right)^2=\frac{9}{4}$$

б) При $$a=-0{,}1$$:

$$9a^2=9\cdot(-0{,}1)^2=9\cdot0{,}01=0{,}09$$
$$\left(9a\right)^2=\left(9\cdot(-0{,}1)\right)^2=(-0{,}9)^2=0{,}81$$
$$-9a^2=-9\cdot(-0{,}1)^2=-9\cdot0{,}01=-0{,}09$$
$$\left(-9a\right)^2=\left(-9\cdot(-0{,}1)\right)^2=(0{,}9)^2=0{,}81$$

Ответ

а) $$\frac{1}{4},\ \frac{9}{4},\ -\frac{1}{4},\ \frac{9}{4}$$;
б) $$0{,}09,\ 0{,}81,\ -0{,}09,\ 0{,}81$$.