Выражение: 7,8*(-2a+1/2b)-2/3*(3a+6b)+2*(1/4a-3/8b)

7ц8/10×(-2а)+7ц8/10×1/2b-2/3×3a-2/3×6b+2×1/4a-2×3/8b= 78/10×(-2a)+78/10×1/2b-2a-4b+1/2a-3/4b= -78/5a+78/5b-2a-4b+1/2a-3/4b= -78/5a-2a+1/2a+78/5b-4b-3/4b= -161/10a+277/10b= 27ц7/10b-16ц1/10а