Could someone me answer these maths questions ☺ *** show step by step guide to how you got the answer***☺

First expand the brackets (4x+1)(x-4)=4x²-16x+x-4 simplfy that 4x²-15x-4
then expand the other bracket (2x-3)(2x-3)=4x²-6x-6x+9=4x²-12x+9 then add them together 8x²-27x+5.
for B if saids to two dp so you use the quadratic formula where a=1 b=-7 and c=-6 so it's -(-7)+-√(-7)²-4(1*-6)/2=11.03 and if you subtract you get 2.97

C: root 50=root(25)*root(2) root 25=5 so it's 5√2 root(32)=root(16)*root(2) and thats 4√2 5√2+4√2=9√2 we can add them because the roots are the same not sure about 4

Iknow one of the answers is a and maybe b but not 100% sure about b