Ok.. Math problems. Algebra 2?

So.. basically im being homeschooled online, and i have been teaching myself due to the fact that my parents are both full time teachers, and i am also a part time English/Chinese tutor. (This all to explain myself.)

Anyway, I cannot for the life of me understand math. It's like a foreign language to me (oh the irony.)

If one of you could help me with it, that'd be amazing.

P=2L+2W ; solve for L

C=2 pi r; solve for r

P= 3r+2s; solve for s

A=1+prt; solve for r

C= 5(F-32)/ 9 ; solve for F

A= h/2(a+b); solve for h

Ok.. so basically what im looking for is how to solve it. You don't have to solve them all, i just desperately want to understand this stuff.

Thank you so much<3

Comments

  • 1. P= 2L +2W

    from the right hand side, we can see that 2 is common to both L and W, therefore, we'll bring it out like this:

    P=2(L+W)

    if this parenthesis are solved for, we'll get back to the original equation. Now didvide both side by 2 to get:

    P/2=2(L+W)/2

    on the right hand side (RHS), 2 will cancel out one another to get:

    P/2=L+W

    now, if W moves to the other side (Left), by crossing over the = sign, it changes it sign from + to -. As in:

    (P/2)-W=L . Therefore,

    L= (P/2)-W. Solved

    2. C=2pi r

    all we need to do here is to find a way to let r be alone and that is by dividing both sides by 2pi:

    C/2pi= 2pi r/2pi

    where 2pi will cancel one another on the RHS to get

    C/2pi= r. Therefore,

    r= C/2pi. Solved.

    3. P=3r+2s.

    All we need to do is to find a way of making s be alone on one side and the rest on the other side. First step is by making 3r cross to the other side and this will change its sign form + to -. As in:

    P-3r=2s

    s is not alone yet, to finalize this, we'll have to divide both sides by 2:

    (P-3r)/2=2s/2

    with 2cancelling 2 on the RHS, we'll be left with:

    (P-3r)/2=s. Therefore,

    s= (P-3r)/2. Solved

    4. A=1+prt

    again, we'll look for a way to make r be alone on one side. Firstly, let 1 cross to the other side where it will change to -1:

    A-1=prt

    now, divide both sides by pt:

    (A-1)/pt= prt/pt

    with pt cancelling out on the RHS, we'll have:

    (A-1)/pt=r. Therefore,

    r= (A-1)/pt. Solved.

    5. C=5(F-32)/9

    can be re written as:

    C/1=5(F-32)/9

    firstly, we'll cross multiply, 5(F-32) will be multiplied by 1 = C will be multiplied by 9.:

    5(F-32)=9C

    now, open the bracket:

    5F-160=9C

    with -160 moving to the other side, it changes sign form - to +:

    5F=9C+160

    divide both sides by 5:

    5F/5=(9C+160)/5

    F=(9C+160)/5. Solved

    or F= (9C/5) + (160/5)

    F= (9C/5) +32. Solved.

    6. A= h/2(a+b)

    firstly, cross multiply:

    h= 2A(a+b). Solved

    please try to understand, it makes me remember when i was coming up in maths :(. Just try, maths is very interesting. ;)

  • Tip: see, all of these problems require you isolate the unknown, e.g. L, on one side via using math operations. I will do the 1st one for you in detail so you may hopefully learn it and do the rest on your own:

    P=2L+2W ; solve for L

    - add - 2W to both sides of the equation

    P - 2W = 2L + 2W - 2W => the 2Ws equal to zero

    - so now you have

    P - 2W = 2L

    - now divide both sides by 2 to get rid of the coefficient of L-the number preceding it

    (P - 2W) / 2 = (2/2) L => 2/2 = 1 in math, you don't write the coefficient of 1

    - now divide each term in the parenthesis on the left by 2

    P/2 - (2W/2) = L

    P/2 - W = L

    or

    L = P/2 - W

  • 1.P=2L+2W ; solve for L

    2L=P-2W

    L=P/2-W

    2.C=2 pi r; solve for r

    r=C/2pi

    3.P= 3r+2s; solve for s

    2s=P-3r

    S=(P-3r)/2

    4.A=1+prt; solve for r

    prt=A-1

    r=(A-1)/pt

    5.C= 5(F-32)/ 9 ; solve for F

    9C=5(F-32)

    9C=5F-160

    5F=9C+160

    F=(9C+160)/5

    F=1.8C+32

    6.A= h/2(a+b); solve for h

    a)if A= h/2*(a+b);

    then

    h=2A/(a+b)

    b) if A= h/ (2(a+b)); then

    h=A*2(a+b)

  • you do the opposite for each side. opposite of addition is subtraction and opposite of multiplication is division.

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