Question five coefficient ?

enter image source here

1 Answer
Jan 20, 2018

#-288750#

Explanation:

#(a+b)^n=sum_(r=0)^na^(n-r)b^r#

#•color(white)(x)T_(r+1)=^nC_ra^(n-r)b^r#

#"here "a=1/5x,b=-25y" and "r=5#

#rArr ^(11)C_5(1/5x)^(11-5)(-25y)^5#

#=462xx1/15625x^6xx-9765625y^5#

#"coefficient "=462xx(-9765625)/15625#

#color(white)("coefficient ")=-288750#