Question

Rezolvati in R urmatoarele ecuatii:
$3(7 - 3x) = 5 - 5x \\ 7(5 - 2x) = 8 - 5x \\ 4(3x + 4) - 7 = 7x \\ 13x - 1 = 6(4x + 9)$
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Answer 1

Explicație pas cu pas:

21-9x=5-5x=>14×=26=>x=26 supra 14=13 supra 7

35-14x=8-5x=>19×=43=>x=43 supra 19

12x+16-7=7x=>5x=8=>x=8 supra 5

13x-1=20x+54=>7x=55=>x=55 supra 7

nu știu dacă este corect

Answer 2

$\it 3(7-3x)=5-5x \Rightarrow 21-9x=5-5x \Rightarrow 21-5=9x-5x \Rightarrow 16=4x \Rightarrow x=4\\ \\ \\ 13-1=6(4x+9) \Rightarrow 13x-1=24x+54 \Rightarrow -1-54=24x-13x \Rightarrow \\ \\ \Rightarrow -55=11x|_{:11} \Rightarrow x=-5$

$\it 7(5-2x)=8-5x \Rightarrow 35-14x=8-5x \Rightarrow 35-8=14x-5x \Rightarrow \\ \\ \Rightarrow 27=9x|_{:9} \Rightarrow x=3$