Indira withdrew $20 from her account every day for 5 days, then deposited $45 into the account. which expression represents the change in the amount in her account?

Step-by-step explanation:

Given : Indira withdrew $20 from her account every day for 5 days, then deposited $45 into the account.

To Find: Which expression represents the change in the amount in her account?

Solution:

We are given that she withdrew in 1 day = $20

So, She withdrew in 5 days =

Since she is withdrawing $100

So, withdrawal = -100

Then she  deposited $45 into the account.

So, expression:

-55 shows the change in the amount in her account

Negative sign shows that balance will be decrease by 55.

Hence expression:

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

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