ВПР 1 №80 Алгебра = ВПТ 5 №7 Математика
Обчисліть:
1. $-{0{,}25}^{-2}:\left(-4^3\right);$
2. $0{,}02\cdot\left(-0{,}5\right)^{-3};$
3. $0{,}4^{-2}{\cdot\left(-\frac{5}{8}\right)}^{-1};$
4. $\left(-1{,}8\right)^0-4^{-1}\cdot{0{,}05}^{-2}.$
Розв'язок:
1. $-{0{,}25}^{-2}:\left(-4^3\right)=$
$= {-\left(\frac{1}{4}\right)}^{-2}:\left(-64\right)=$
$= -4^2:\left(-64\right)=$
$= -16:\left(-64\right)=\frac{16}{64}=\frac{1}{4};$
2. $0{,}02\cdot\left(-0{,}5\right)^{-3}=$
$= 0{,}02\cdot\left(-\frac{1}{2}\right)^{-3}=$
$= 0{,}02\cdot\left(-2\right)^3=$
$= 0{,}02\cdot\left(-8\right)=-0{,}16;$
3. $0{,}4^{-2}{\cdot\left(-\frac{5}{8}\right)}^{-1}=$
$= \left(\frac{2}{5}\right)^{-2}\cdot\left(-\frac{8}{5}\right)=$
$= \left(\frac{5}{2}\right)^2\cdot\left(-\frac{8}{5}\right)=$
$= \frac{25}{4}\cdot\left(-\frac{8}{5}\right)= -\frac{25\cdot8}{4\cdot5}=-10;$
4. $\left(-1{,}8\right)^0-4^{-1}\cdot{0{,}05}^{-2}=$
$= 1-\frac{1}{4}\cdot\left(\frac{1}{20}\right)^{-2}=$
$= 1-\frac{1}{4}\cdot{20}^2=1-\frac{1}{4}\cdot400=$
$= 1-100=-99.$