Como se resuelve y que debo hacer?​

How to write four times a number,minus 6,is equal to theee times the number+8 as an equqtion

In trapezoid abcd, ac is a diagonal and ∠abc≅∠acd. find ac if the lengths of the bases bc and ad are 12m and 27m respectively.

The first week samantha learned to read braille, she could read 10 words per minute. in the second week she increased her speed by 20%. in the third week she increased her speed again by another 25%. how many words could she read per minute by the third week? hurry and tell me!