Question

afla valoarea termenului necunoscut:60x90-50x {84-[45-(7xa-9)x2]}-10=2240.

Answer 1

5400-50x{84-[14xa-18]}-10=2240

notam 14xa-10=b

5400-(4200-50b)-10=2240

notam:4200-50b=c

5400-c-10=2240

c=5400-10-2240

c=3150

4200-50xb=3150

50xb=4200-3150

50xb=1050

b=1050:50

b=21

14xa-10=21

14xa=31

a=31:14

Answer 2

60x90-50x{84-[45-(7xa-9)x2]}-10=2240
5400-50x{84-[45-(7xa-9)x2]}=2240+10
5400-50x{84-[45-(7xa-9)x2]}=2250
50x{84-[45-(7xa-9)x2]}=5400-2250
50x{84-[45-(7xa-9)x2]}=3150
84-[45-(7xa-9)x2=3150:50
84-[45-(7xa-9)x2=63
45-(7xa-9)x2=84-63
45-(7xa-9)x2=21
(7xa-9)x2=45-21
(7xa-9)x2=24
7xa-9=24:2
7xa-9=12
7xa=12+9
7xa=21
a=21:7
a=3