2 Type the correct answer in each box. Use numerals instead of words.
Multiply the expressions.
3.12 + 21 - 21
-212 - 21 + 12
212 + 251 + 63
612 + 71 - 49
If a = 1, find the values of b, c, and d that make the given expression equivalent to the expression below.
ar +
CI + d
b=
,and du
,C=
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− r + 9 / 2  ( r − 2 )

answer: 4/6 =5/7.5

step-by-step explanation: it is based on scale and the scale between the two is 1.25. the answer is correct but i dont know if i explained it right

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