57/8 x (2 4/5 ÷ 7) ahh i'm to stupid for this

Convert 5 7/8 to an improper fraction. Use this rule: a b/c = ac + b/c

5 × 8 + 7/8 × 2 4/5 ÷ 7

Simplify 5 × 8 to 40

40 + 7/8 × 2 4/5 ÷ 7

Simplify 40 + 7 to 47

47/8 × 2 4/5 ÷ 7

Convert 2 4/5 to an improper fraction using the same rule from the previous step.

47/8 × 2 × 5 + 4/5 ÷ 7

Simplify 2 × 5 to 10

47/8 × 10 + 4/5 ÷ 7

Simplify 10 + 4 to 14

47/8 × 14/5 ÷ 7

Use this rule: a ÷ b/c = a × c/b

47/8 × 14/5 × 1/7

Proceed to use this rule: a/b × c/d = ac/bd

658/8 × 5 × 7

Simplify 8 × 5 × 7 to 280

658/280

Simplify

47/20

Convert to mixed fraction

the value of v.w= -12.

step-by-step explanation:

we are given three vector r,v and w as:

r = < 5, -5, -2> ; v = < 2, -8, -8> ; w = < -2, 6, -5>

we know that r,v and w could also be represented as:

r=5i-5j-2k

v=2i-8j-8k

and w= -2i+6j-5k

where i,j and k are the unit vectors of x,y and z-axis respectively.

also we know that it has the following property:

i.i=1 ; j.j=1; k.k=1

and i.=j.i=i.k=k.i=j.k=k.j=0

i.e. when we multiply two vectors or we find it's dot product we need to only multiply the components of x coordinates with each other; y with each other and z with each other.

hence, v.w= (2i-8j- -2i+6j-5k)

                  = 2×(-2)+(-8)×(6)+(-8)×(-5)

                  = -4-48+40

                  = -12

hence, v.w= -12

i found two solutions,   n = 2 • ± √3 = ± 3.4641

step-by-step explanation: