Question

Ex 3 : Afla numarul necunoscut : (a x 9 - 78 :2 ) + 4 x 25 = 1492

Answer 1

$(9a-39)+100=1492 \\ 9a-39=1492-100 \\ 9a=1392 +39\\ a=1431:9 \\ a=159$

Answer 2

=9a-39+100=1492
=9a-39=1492-100
=9a-39=1392
=9a=1392+39
=9a=1431
=a=1431:9
=a=159