Question

21/x+2+21/x-2 =10
what is the answer please explain me.​

Answer 1

Answer:

here is your answer

hope it helps

Answer 2

Question :

$\bf{\dfrac{21}{x+2}+\dfrac{21}{x-2}=10}}$

Solution :

$\longrightarrow \sf{\dfrac{21}{x+2}+\dfrac{21}{x-2}=10}\\\\ \\ \longrightarrow \sf{\dfrac{21(x-2)+21(x+2)}{(x+2)(x-2)}=10} \\ \\ \\ \longrightarrow \sf{\dfrac{21x-42+21x+42}{x^{2}-2^{2}}=10} \qquad \qquad \qquad \bigg(a^{2}-b^{2} = (a + b)(a - b)\bigg) \\ \\ \\ \longrightarrow \sf{\dfrac{21x +21x}{x^2 -4}=10} \\ \\ \\ \longrightarrow \sf{\dfrac{42x}{x^2 -4}=10} \\ \\ \\ \longrightarrow \sf{42x=10(x^2 - 4)} \\ \\ \longrightarrow \sf{42x=10x^2 -40}\\ \\ \longrightarrow \sf{10x^2-42x -40=0}$

$\longrightarrow \sf{2(5x^2-21x -20)=0} \\\\ \longrightarrow \sf{(5x^2-21x -20)=0/2} \\\\ \longrightarrow \sf{5x^2-21x -20=0} \\\\ \longrightarrow \sf{5x^2-(25-4)x -20=0} \\\\ \longrightarrow \sf{5x^2-25x+4x -20=0} \\\\ \longrightarrow \sf{5x(x-5)+4(x-5)=0}\\\\ \longrightarrow \sf{(x-5)(5x+4)=0}$

x - 5 = 0

⇒ x = 5

5x + 4 = 0

⇒ 5x = -4

⇒ x = -4/5