Question

Subliniati factorul comun si efectuati calculele in doua moduri; a si b sunt nr intregi:
a)7×8+7×(-3)
b)-10×4-(-10)×9
c)-3×1+(-3)×2+(-3)×(-13)
d)12×(-8)+12×(+20)
e)-17×25-(-17)×(-25)+(-40)×(-17)
f)4×a-4×b+4×(b-a+1); a apartine Z, b apartine Z
g)-9×(-3)+(-9)×21-(-9)×(-6)
h)4×(a+b)-4×a-4×b; a apartine Z, b apartine Z

Answer 1

Sper ca te-am ajutat!

Answer 2

Răspuns:

Explicație pas cu pas:

a)  7 × 8 + 7 × ( - 3 ) = 56 - 21 = 35 → primul mod

    7 × ( 8 - 3 ) = 7 × 5 = 35 → al doilea mod

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b)   - 10 × 4 - ( - 10 ) × 9 = - 40 + 90 = 50 → primul mod

      ( - 10) × ( 4 - 9 ) = ( - 10 ) × ( - 5 ) = 50 → al doilea mod

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c) - 3 × 1 + ( - 3 ) × 2 + ( - 3 ) × ( - 13 ) = - 3 - 6 + 39 = - 9 + 39 = 30

   ( - 3 ) × ( 1 + 2 - 13 ) = ( - 3 ) × ( - 10 ) = 30 → al doilea mod

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d)  12 × ( - 8 ) + 12 × ( + 20 ) = - 96 + 240 = 144 → primul mod

    12 × ( - 8 + 20 ) = 12 × 12 = 144 → al doilea mod

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e) - 17 × 25 - ( - 17 ) × ( - 25) + ( - 40 ) × ( - 17 ) =

     = - 425 - 425 + 680 = - 850 + 680 = - 170

   - 17 × ( 25 + 25 - 40 ) = - 17 × 10 = - 170 → al doilea mod

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f)    4 × a - 4 × b + 4 × ( b - a + 1 ) = 4 × a - 4 × b + 4 × b - 4 × a + 4 = 4

    4 × ( a - b + b - a + 1 ) = 4 × 1 = 4 → al doilea mod

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g)  - 9 × ( - 3 ) + ( - 9 ) × 21 - ( - 9 ) × ( - 6 ) = 27 - 189 - 54 =- 216

     - 9 × ( - 3 + 21 + 6 ) = - 9 × 24 = - 216 → al doilea mod

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h)  4 × ( a + b ) - 4 × a - 4 × b = 4 × ( a + b ) - 4 × ( a + b )

= ( a + b ) × ( 4 - 4) = ( a + b ) × 0 = 0 → primul mod

4 × a + 4 × b - 4 × a - 4 × b = ( 4 × a - 4 × a ) + ( 4 × b - 4 × ) = 0 - 0 = 0 → al doilea mod