I'll do questions #2# and #4#.
#2.# We need to factor the numbers within the square roots.
#=>5sqrt(4 xx 3) - 2sqrt(25 xx 3) + 3sqrt(9 xx 3)#
#=>5(2)sqrt(3) - 2(5)sqrt(3) + 3(3)sqrt(3)#
#=>10sqrt(3) - 10sqrt(3) + 9sqrt(3)#
#=>9sqrt(3)#
The numerical coefficient is #9#.
#4.# This is a trinomial factoring problem. When we want to factor a trinomial of the form #y = ax^2+bx + c, a!=1, 0#, we need to find two numbers that multiply to #ac# and that add to #b#.
#=>10r^2 - 8r + 35r - 28#
#=>2r(5r - 4) + 7(5r - 4)#
#=>(2r + 7)(5r - 4)#
The value of #a+ b + c + d# is #2 + 7 + 5 - 4 = 10#
Hopefully this helps!