Can anyone help explain this my daughter is 7 does not understand it

Find the greatest common factor of -30x 4 yz 3 and 75x 4 z 2.

Acircle has a radius of 12.6cm what is the exact length of an arc formed by a central angle measuring 120

The second term of an arithmetic sequence is 30. the fifth term is 90.calculatei). the commor difference of the sequence ii). the first term of the sequence tje first, second and fifth terms of the arithmetic sequence are the first three terms of a geometric sequence calculate the seventh term of the geometric sequence