Explicație pas cu pas:
[tex]$\mathbf{a)2 \times (39 \div (16 - 24 \div 4) + (9 + 6 \div 3) \times 7)}$[/tex]
[tex]$\mathbf{2 \times (39 \div (16 - 6) + (9 + 2) \times 7)}$[/tex]
[tex]$\mathbf{2 \times (39 \div 10 + 11 \times 7)}$[/tex]
[tex]$\mathbf{2 \times (3.9 +77) }$[/tex]
[tex]$\mathbf{2 \times 80.9 = 161.8}$[/tex]
[tex]$\mathbf{b)9 {}^{12} \times 9 {}^{15} \div (9 {}^{3} ) {}^{9} }$[/tex]
[tex]$\mathbf{9 {}^{12} \times {9}^{15} \div 9 {}^{3 \times 9} }$[/tex]
[tex]$\mathbf{9 {}^{12} \times 9 {}^{15} \div {9}^{27} }$[/tex]
[tex]$\mathbf{ {9}^{12 + 15 - 27 } = {9}^{0} = 1 }$[/tex]
[tex]$\mathbf{c)19 {}^{0} + {1}^{53} + {2}^{3} + {0}^{1000} }$[/tex]
[tex]$\mathbf{1 + 1 + 8 + 0 = 2 + 8 = 10}$[/tex]
[tex]$\mathbf{d)28 + 2 \times (2660 + 76 \div x) \div 893 = 34}$[/tex]
[tex]$\mathbf{28 + 2 \times \frac{2660x - 76}{x} \times \frac{1}{893} = 34 }$[/tex]
[tex]$\mathbf{28 + 2 \times \frac{19(140x - 4)}{x} \times \frac{1}{893} = 34}$[/tex]
[tex]$\mathbf{28 + 2 \times \frac{140x - 4}{x} \times \frac{1}{47} = 34 }$[/tex]
[tex]$\mathbf{28 + \frac{280x - 8}{47x} = 34}$[/tex]
[tex]$\mathbf{ \frac{280x - 8}{47x} = 34 - 28}$[/tex]
[tex]$\mathbf{ \frac{280x - 8}{47x} = 6 }$[/tex]
[tex]$\mathbf{280x - 8 = 282x}$[/tex]
[tex]$\mathbf{280x - 282x = 8}$[/tex]
[tex]$\mathbf{ - 2x = 8}$[/tex]
[tex]$\mathbf{x = 8 \div ( - 2) = - 4}$[/tex]
Bafta!
