Iwant to solve that problem but i don't know how

You need to solve for n. So distribute 4 to inside the parenthesis. 4(1+5n)=4+20n. Combine like terms on the right side of the equation. -6n+8n=2n. The equation is now 4+20n=-14+2n. Subtract 4 from bit sides because you need to get y by itself. You get 20n=-18+2n. Subtract 2n from each side to get 18n=-18. Divide by 18 on each side to get n=-1. The answer to the equation is n=-1. Hope this helps! ;)