Question

va rog ajutați ma la exercițiul 22. variantele d,e si f va rog frumos ​

Answer 1

Răspuns:

d)

( aducem la acelasi numitor comun => 40 si vom obtine ecuatia : )

20x + 1 = 24x

1 = 24x - 20x

1 = 4x

x = 1/4

e)

( aducem la acelasi numitor comun => 45 si vom obtine ecuatia : )

9x - 5 = 12x

9x - 12x = 5

- 3x = 5

x = - 5/3

f)

( aducem la acelasi numitor comun => 24 si vom obtine ecuatia : )

28 - 3x = 46x

28 = 46x + 3x

28 = 49x

x = 28/49  (simplif. cu 7)

x = 4/7

Answer 2

$\it d)\ \ \dfrac{x}{2}+\dfrac{1}{40}=\dfrac{3x}{5}|_{\cdot40} \Rightarrow 20x+1=24x|_{-20x}\Rightarrow 1=4x|_{:4} \Rightarrow x=\dfrac{1}{4}\\ \\ \\ e)\ \dfrac{x}{5}-\dfrac{1}{9}=\dfrac{4x}{15}|_{\cdot45} \Rightarrow 9x-5=12x|_{-9x} \Rightarrow -5=3x|_{:3}\Rightarrow x=-\dfrac{5}{3}\\ \\ \\ f)\ \dfrac{7}{6}-\dfrac{x}{8}=\dfrac{23x}{12}|_{\cdot24}\Rightarrow28-3x=46x|_{+3x}\Rightarrow 28=49x \Rightarrow x=\dfrac{\ 28^{(7}}{49}=\dfrac{4}{7}$