Please Help Me out?

Question

I'm kinda stuck on how to do these if someone could work it a few out for me i'd appreciate it I don't remember the processes of this crap

7(a+1)-3a=5+4(2a-1)


0.5(2x+3/4)-1/3 (.1+x)=1

solve for variable 'v' ; h=vt-5t^2

'b2'; A= 1/2h(b1+b2)

Answer 1

You need to remember the "rules" of expanding an expression. In the first, all terms in ( ) must be multiplied by the multiplier. So you get
7a+7 -3a = 5 + 8a -4
Next, we collect "like terms". In this case, the like terms are those with "a". Also, we move these to one side of the equation, and constants to the other side. Doing this: 7+4-5 = 8a-7a+3a or
.... 6 = 4a. Then we divide both sides by the coefficient of a to get an answer, simplify if necessary. Doing this a= 6/4 or 3/2.

The second one is the same except you have fractions and decimals.

The next two require you to isolate the given variable on one side of the equation and everything else on the other.

For the "v" problem we first move terms that DONT have v in them to the other side of the eqtn.
So... h+5t^2 = vt.
Then we divide both sides by t, leaving us the "1v".
So. (h/t)+5t = v.

Answer 2

7a+7-3a = 5+8a-4
combining like terms:
4a+7 = 1+8a
combining like terms again;
6 = 4a
6/4 = a

h = vt - 5t^2
h = t(v-5t)
h/t = v-5t
h/t + 5t = v

Answer 3

in my head a = 1.5