Question

 Aflati cate nr. de  forma 7x3y  sunt divizibile cu :                                                                                             a) 2                  b)5              c)10

Answer 1

7x3y=divizibile cu 2 = 7030, 7130, 7230, 7330, 7430, 7430,7630,7730, 7830, 7930,7032, 7132,
divizibile cu 5 = 7030,7130, 7230,7330, 7430,.... 7035
divizibile cu 10 = 7030,7130, 7430, ....7930

Answer 2

7x3y sunt divizibile cu : a) 2 ⇒y∈{0,2,4,6,8}⇒x∈{0,1,2,3,4,5,6,7,8,9}
7030,7130,7230,7330,7430,7530,7630,7830,7930
7032,7132,7332,7432,7532,7632,7832,7932
7034,7134,7234,7334,7534,7634,7834,7934
7036,7136,7236,7336,7436,7536,7836,7936
7038,7138,7238,7338,7438,7538,7638,7938


b)5 ⇒y∈{0,5}⇒x∈{0,1,2,3,4,5,6,7,8,9}
7130,7230,7330,7430,7530,7630,7730,7830,7930,7035,7135,7235,7335,7435,7635,7735,7835,7935


c)10 ⇒y=0⇒x∈{0,1,2,3,4,5,6,7,8,9}
7130,7230,7330,7430,7530,7630,7730,7830,7930