Răspuns:
Explicație pas cu pas:
a) ( x-1)/(2x+10) = 1/3 -> proportie
3 ( x - 1 ) = 2 x + 10 -> produsul mezilor = produsul extremilor
3 x - 3 = 2 x + 10
3 x - 2 x = 10 + 3
x = 13
Verific:
( 13-1)/2(13+5) = 6/18 = 1/3
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b)
(x+1)/(3x-1) = 1/2
3 x - 1 = 2(x+1)
3 x - 1 = 2 x + 2
3 x - 2 x = 2 + 1
x = 3
Verific:
(3+1)/(9-1) = 4/8 = 1/2
