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Aflati numarul X.
a)280:X+60=80
b)65-(X-275)=40
c)X:5+20=160


Răspuns :

a)
280 :x = 80-60
280:x = 20
x= 280:20
x= 14

b)
x-275 = 65-40
x-275 = 25
x=25+275
x=300

c)
x:5 = 160 -20
x:5=140
x= 140x5
x= 700
∅ Rezolvare :



¹) 280 : x + 60 = 80 ⇔ 280 : x = 80 — 60 ⇔ 280 : x = 20 ⇔ x = 280 : 20 ⇔ x = 14 ⇔ S = { 14 }

²) 65 — ( x — 275 ) = 40 ⇔ x — 275 = 65 — 40 ⇔ x — 275 = 25 ⇔ x = 275 + 25 ⇔ x = 300 ⇔ S = { 300 }

³) x : 5 + 20 = 160 ⇔ x : 5 = 160 — 20 ⇔ x : 5 = 140 ⇔ x = 140 · 5 ⇔ x = 700 ⇔ S = { 700 }