Question

Determina numarul necunoscut din egalitatile21+124569-2x a-107=6737
(18xb-1278):149=36
[(c+41+56):2-20]:19=3

Answer 1

21+124 569-2×a=6 737+107
21+124 569-2×a=6 844
124 590 -2×a=6 844
2×a=124 590-6 844
2×a= 11 746
a=11 746 : 2
a=5 873

(18×b-1 278):149=36
18×b-1 278=36×149
18×b-1 278=5 364
18xb=5364+1 278
18×b= 6 642
b=6 642:18
b=369

[(c+41+56):2-20]:19=3
(c+41+56):2-20=3×19
(c+41+56):2-20=57
(c+41+56):2=57+20
(c+41+56):2=77
c+41+56=77×2
c+41+56=154
c+41=154-56
c+41=98
c=97-41
c=56