Question

Afla Nr necunoscut a din:a) 7a-35=56 b) (8+a):21=100 c)(29-a)×20=400 d){[2a+3)×2+3]×2+3}×2+3=85

Answer 1

7a=56+35
7a=91
a=91:7
a=13

(8+a):21=100
8+a=100x21
8+a=2100
a=2100-8
a=2092

(29-a)x20=400
(29-a)=400:20
29-a=20
a=29-20
a=9

Answer 2

7a-35=56
7a=56+30
7a=91
a=91:7
a=13

(8+a):21=100
8+a=2100
a=2100-8
a=2092


(29-a)x20=400
29-a=400:20
29-a=20
a=29-20
a=9

{[( 2a+3)x2+3]x2+3}x2+3=85
{[(2a+3)x2+3]x2+3 }x2=85-3
{[(2a+3)x2+3]x2+3}x2=82
[(2a+3)x2+3]x2+3=82:2
[(2a+3 ) x2+3 ]x2+3=41
[(2a+3)x2+3]x2=41-3
[(2a+3)x2+3]x2=38
[(2a+3) x2 +3 ]=38:2
(2a+3)x2+3=19
(2a+3)x2=19-3
(2a+3)x2=16
2a+3=16:2
2a+3=8
2a=5
a=5:2
a=2,5