let 1 cross to the other side where it will change to -1:A-1=prtnow, divide both sides by pt:(A-1)/pt= prt/ptwith pt cancelling out on the RHS, well have:(A-1)/pt=r. Therefore,r= (A-1)/pt. Solved.......
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. ;)
you do the opposite for each side. opposite of addition is subtraction and opposite of multiplication is division.
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
