Eighteen more than seven times a number is 19.

18+7x=19

Step-by-step explanation:

18+7x=19

More than in math represents addition, and the "a number" phrase is your variable, which is x.

(this is for if you're supposed to solve the equation)

7x=19-18

7x=1

x=1/7

I'm not really sure if you're supposed to actually solve the problem or write out the equation the question is asking for, but just with the context I'm given hopefully you don't have to) ;D

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

is means division by fractions

step-by-step explanation: