Question

Determina termenul necunoscut din egalitatile urmatoare: a). (3 × a +5 ) × 5 - 3 =292 ; b). (b - 5 ) ×2 =30; c). ( c-17 ) ×3 +15=45; d). [2× (d-30) -45 ×3 =165 .

Answer 1

a) (3×a+5)×5-3=292
(3×a+5)×5=292+3
(3×a+5)×5=295
3×a+5=295:5
3×a+5=59
3×a=59-5
3×a=54
a=54:3
a=18

b) (b-5)×2=30
b-5=30:2
b-5=15
b=15+5
b=20

c) (c-17)×3+15=45
(c-17)×3=45-15=30
c-17=30:3
c-17=10
c=17+10=27

d) 2×(d-30)-45×3=165
2×(d-30)-135=165
2×(d-30)=165+135= 300
d-30=300:2
d-30=150
d=150+30
d=180