Question

1)Determina x pentru care : a) __ __ b)
12x + x2 =177 ; 1x3+3x=188
ala nu e ori e x

2) Determina toate nr de forma __ __
xy care sunt cu 45 ,aro decat yx

Answer 1

1)b)12x+x2=177=>x=5=>125+52=177 x=5,deci
1x3+3x=188=>x=5=>153+35=188 deci x=52

2)xy=yx+45
10x+y=10y+x+45
9 (x-y)=45,deoarece:(10x-x)-(10y-y)=45=>9x-9y
x-y=45÷9
x-y=5
x €{6,7,8,9.}
y €{1,2,3,4.}
xy €{61,72,83,94.}