А) (2a+3x)(5a-x)-(a+x)(10a-3)=10a²+15ax-3x²-2ax-(10a²+10ax-3a-3x)=10a²-3x²+13ax-10a²-10ax+3a+3x=-3x²+3ax+3a+3x
b) (7x+1)(x-5)+(3x-2)(2x+7)=7x²+x-35x-5+6x²-4x+21x-14=13x²-17x-19
c) -0,1x(2x²+6)(5-4x²)=-0,1x(10x²+30-8x⁴-24x²)=-0,1x(-14x²+30-8x⁴)=1,4x³-3x+0,8x⁵
M²(a-2)+n(2-a)=m²(a-2)-n(a-2)=(a-2)(m²-n)
<span>(5х-16)(5х+16)-25х ²-29 =5х²-16²-25х²-29=<u>25х²</u>-256-<u>25х²</u>-29 =-256-29 =-285</span>