You need to distribute the -5 and(2x-7y+3)which gives you -10x+35y-15. Now you have 2x-10x+35y-15+-8. Combine like terms, 2x-10x=-8x, also combine -15+-8= -23. The answer would be -8x+35y-23.
8n + 5 = 139
You would re-Arrange it to make it
8n = 139 + 5
Then take minus five to make it look like
8n=134
Next step would be to divide
Divide 8 on both sides which would leave you with
N= 67 over 4
you will have to convert it if you don’t want a fraction