Question

calculați:
a). [(49×28+49×15) :9+49×7] :10+49 = b). {14×4+15×16-20×[(5²-3²+2³):8-2]}:10= c). 10²-(5²×5-6×7+17×7⁰) : 10×3²= ​

va rog frumos!!!!!​

Answer 1

Explicație pas cu pas:

a). [(49×28+49×15) :9+49×7] :10+49 =

$= \left[\frac{49(28 + 15)}{9} + 49 \times 7 \right]\div 10 + 49 = \\ = (\frac{49 \times 43}{9} + \frac{49 \times 7 \times 9}{9} ) \div 10 + 49 = \\ = \frac{49(43 + 63)}{9 \times 10} + 49 = \frac{49 \times 106 + 49 \times 90}{90} \\ = \frac{49(106 + 90)}{90} = \frac{49 \times 196}{90} = \frac{2 \times {7}^{4} }{{3}^{2} \times 5} \\ = 106.7(1)$

b). {14×4+15×16-20×[(5²-3²+2³):8-2]}:10 =

$= \left[56 + 240 - 20 \times(24 \div 8 - 2) \right] \div 10 \\ = \left[296 - 20 \times(3 - 2) \right] \div 10 \\ = (296 - 20) \div 10 = 276 \div 10 = 27.6$

c). 10²-(5²×5-6×7+17×7⁰) : 10×3² =

$= 100 - (25 \times 5 - 42 + 17 \times 1) \div 10 \times 9 \\ = 100 - (125 - 42 + 17) \div 10 \times 9 \\ = 100 - 100 \div 10 \times 9 = 100 - 10 \times 9 \\ = 100 - 90 = 10$