Question 763103

{{{(-a^2+5a-8)-(-4a^2+6a-5)}}}...I guess you have this; first eliminate parenthesis, be careful if minus sign in front, the rule for the "sign" in front of the parenthesis:  the plus sign inside of the parenthesis become a minus (negative) sign and the negative sign become a positive

{{{-a^2+5a-8+4a^2-6a+5)}}}

{{{3a^2-a-3)}}}