a.\(697:\frac{15.a+364}{a}=17\)

\(\Leftrightarrow\frac{15.a+364}{a}=41\)

\(\Leftrightarrow15.a+364=41.a\)

\(\Leftrightarrow15.a-41.a=-364\)

\(\Leftrightarrow a.\left(15-41\right)=-364\)

\(\Leftrightarrow a.\left(-26\right)=-364\)

\(\Leftrightarrow a=14\)

b.\(92.4-27=\frac{a+350}{a}+315\)

\(\Leftrightarrow368-27=\frac{a+350}{a}+315\)

\(\Leftrightarrow\frac{a+350}{a}+315=341\)

\(\Leftrightarrow\frac{a+350}{a}=26\)

\(\Leftrightarrow a+350=a.26\)

\(\Leftrightarrow350=a.26-a\)

\(\Leftrightarrow a.\left(26-1\right)=350\)

\(\Leftrightarrow a.25=350\)

\(\Leftrightarrow a=14\)

a) x¹⁵ = x => x¹⁵ - x = 0 => x. x¹⁴ - x = 0 => x. (x¹⁴ - 1) = 0 => x = 0 hoặc x¹⁴  - 1 = 0 

x¹⁴ - 1 = 0 => x¹⁴ = 1 => x = 1 hoặc x = -1

b) => (x - 5)⁴ - (x - 5)⁶ = 0 => (x - 5)⁴ - (x - 5)². (x - 5)⁴ = 0 => (x - 5)⁴ . [1 - (x - 5)²] = 0

=> (x - 5)⁴ = 0 hoặc 1 - (x - 5)^{2 = 0} 

+) (x - 5)⁴ = 0 =>x - 5 = 0 => x = 5

+) 1 - (x - 5)² = 0 => (x - 5)² = 1 => x - 5 = 1 hoặc x - 5 = -1

=> x = 6 hoặc x = 4

Vậy...

c) => \(\frac{15.a+364}{a}=\frac{697}{17}\Rightarrow15+\frac{364}{a}=41\Rightarrow\frac{364}{a}=41-15=26\)=> a = 364: 26 = 14

d) => 368 - 27 = 1 + \(\frac{350}{a}\) + 315 

=> 341 = 316 + \(\frac{350}{a}\)=> 350/a = 341 - 316 = 25 => a = 350/25 = 14

\(a.697:\dfrac{15a+364}{a}=17\\ =>\dfrac{15a+364}{a}=697:17=41\\ =>41a=15a+364\\ =>41a-15a=364\\ =>26a=364=>a=\dfrac{364}{26}=14 \\ b.92.4-27=\dfrac{a+350}{a}+315 \\ =>92.4-27-315=\dfrac{a+350}{a}\\ =>26=\dfrac{a+350}{a}\\ =>26a=a+350=>25a=350 \\ =>a=14\)