Question

Punctele "7" si "8".VA ROGGGG!!!! DAU

Answer 1

7) 3ⁿ + 3ⁿ x 3² = 3ⁿ(1 + 1 x 3²) = 3ⁿ x 10
    2ⁿ + 2ⁿ⁺¹ + 3 x 2ⁿ⁺² = 2ⁿ(1 + 2 + 3 x 4) = 2ⁿ x 15
    3ⁿ x 2 x 5 supra 2ⁿ x 3 x 5/simplifcam cu 5 = 3ⁿ x 2 supra 2ⁿ x 3/simplificam cu 2 x 3 = 3ⁿ⁻¹ supra 2ⁿ⁻¹ = 3 supra 2 => n = 2
8) $\frac{a + 2}{10} = \frac{b+1}{5} = \frac{4}{c+3}$
    => 5a + 10 = 10b + 10 => 5a = 10b /:5 => a = 2b
    => ac + 3a + 2c + 6 = 40
    => a(c + 3) + 2c = 34
    => 2b(c + 3) + 2c = 34 => b(c+3) + c = 17
    17 : b = 2c + 3 
     b = 17 :(2c + 3) , cum 17 = prim => 2c + 3 = 17 => 2c = 14 => c = 14:2=7
     10a + 14 = 34 => 10a = 20 => a = 20 : 10 =2 
     a = 2b => b = 2 : 2 = 1