Find the value of a and b in the expansion of \((1-3x)^2(1+ax)^8 = 1+10x+bx^2+\cdots\)
9 a^8 x^10 - 6 a^8 x^9 + a^8 x^8 + 72 a^7 x^9 - 48 a^7 x^8 + 8 a^7 x^7 + 252 a^6 x^8 - 168 a^6 x^7 + 28 a^6 x^6 + 504 a^5 x^7 - 336 a^5 x^6 + 56 a^5 x^5 + 630 a^4 x^6 - 420 a^4 x^5 + 70 a^4 x^4 + 504 a^3 x^5 - 336 a^3 x^4 + 56 a^3 x^3 + 252 a^2 x^4 - 168 a^2 x^3 + 28 a^2 x^2 + 72 a x^3 - 48 a x^2 + 8 a x + 9 x^2 - 6 x + 1
(27 terms)
