Write in Standard Form a^2+4a-5a^2-a

$a^{2} + 4 a - 5 a^{2} - a$

To write a polynomial in standard form, simplify and then arrange the terms in descending order.

$a x^{2} + b x + c$

Subtract $5 a^{2}$ from $a^{2}$ .

$- 4 a^{2} + 4 a - a$

Subtract $a$ from $4 a$ .

$- 4 a^{2} + 3 a$