Question

Afla valoarea numarului necunoscut din urmatoarele expresii: a. 426-(460-10xa)=366 b. [(58xa-80):25]x64=1280 c. [(a+54)x4+6]x4-184+800 d. 1100-[(512-144:a)x2]-171=1 e. [(420:a)x4+24]:4=11

Answer 1

a)
426-(460-10xa)=366
460-10a=426-366
460-10a=60
10a=460-60
10a=400
a=400÷10
a=40

b)
[(58×a-80)÷25]×64=1280
(58×a-80)÷25=1280÷64
58×a-80= 20×25
58×a=500+80
a=580÷58
a=10

c)
[(a+54)x4+6]x4-184+800
(a+54)×4+6=984÷4=246
(a+54)×4=246-6=240
a+54=240÷4=60
a=60-54
a=6
d)
1100-[(512-144÷a)×2]=171+1=172
(512-144÷a)×2=1100-172=928
512-144÷a=928÷2=464
144÷a=512-464=46
a=144÷46
a=3

e)
(420:a)×4+24=11×4
(420:a)×4+24=44
(420:a)×4=44-24
(420:a)×4=20
420:a=20:4
420:a=5
a=420:5
a=84