Răspuns :
4)
a) 5 x + 7 = 52
5 x = 52 - 7
5 x = 45
x = 45 : 5
x = 9
b)
16 = 2 x - 8
2 x - 8 = 16
2 x = 16 + 8
2 x = 24
x = 24 : 2
x = 12
V: 2 × 12 - 8 = 24 - 8 = 16
5)
3 y = 27 ⇒ y = 27 : 3 ⇒ y = 9 ⇒ y = 3²
y² = 9² = 9 × 9 = 81
6)
9¹⁵ si 27¹¹
9¹⁵ = ( 3²)¹⁵ = 3²ˣ¹⁵ = 3³⁰
27¹¹ = ( 3³ )¹¹ = 3³ ˣ ¹¹ = 3³³
3³⁰ < 3³³
9¹⁵ < 27¹¹
[tex]4) \\ \\ 5x + 7 = 52 \\ \\ 5x = 52 - 7 = 45 \\ \\ \frac{5x}{5} = \frac{45}{5} \\ \\ x = 9 \\ \\ 16 = 2x - 8 \\ \\ 2x - 8 = 16 \\ \\ 2x = 8 + 16 = 24 \\ \\ \frac{2x}{2} = \frac{24}{2} \\ \\ x = 12 \\ \\ 5) \\ \\ {3}^{y} = {3}^{3} \\ \\ y = 3 \\ \\ {3}^{2} = 9 \\ \\ {y}^{2} = {9}^{2} = 9 \times 9 = 81 [/tex]