Hi,
To solve for another variable:
a) Eliminate any fractions and/or parentheses.
b) Move all the terms with the subject variable to one side of the equation and move all terms without the subject variable to the other side of the equation. Combine any like terms.
c) Factor the subject variable out as a GCF on one side of the equation.
d) Divide both sides of the equation by the expression left behind when taking out the GCF. This gets the subject variable alone.
e) If the subject variable is squared, take the square root of both sides. Remember this could require a +/- sign in front of the remaining radical. In this case on # 11, since "r" is the radius and it is always positive, the +/- sign is not needed.
1. 4(x-2y)=3(2x-y) (Make x the subject)
4x - 8y = 6x - 3y
-2x = 5y
x = -5/2y <== ANSWER
2. p(a-b)=q(a+b) (Make a the subject)
pa - pb = qa + qb
pa - qa = pb + qb
a(p - q) = pb + qb
a = (pb + qb)/(p - q) <== ANSWER
3. A=2ab^2 + ac (Make a the subject)
A = a(2b² + c)
a = A/(2b² + c) <= ANSWER
4. s(t+1)=2r+3 (Make r the subject)
st + s = 2r + 3
st + s - 3 = 2r
r = (st +s - 3)/2 <== ANSWER
5. st-r=2r-3t (Make t the subect)
st + 3t = 3r
t(s + 3) = 3r
t = (3r)/(s + 3) <== ANSWER
6. ax=b-cx (Make x the subject)
ax + cx = b
x(a + c) = b
x = b/(a + c) <== ANSWER
7. x(a-b)=x+b (Make x the subject)
ax - bx = x + b
ax - bx - x = b
x(a - b - 1) = b
x = b/(a - b - 1) <== ANSWER
8. a-bx=dx-a (Make x the subject)
-dx - bx = -2a
dx + bx = 2a
x(d + b) = 2a
x = (2a)/(d + b) <== ANSWER
9. x(c-d)=c(d-x) (Make x the subject)
cx - dx = cd - cx
2cx - dx = cd
x(2c - d) = cd
x = (cd)/(2c - d) <== ANSWER
10. P=2 pi r + 4r (Make r the subject)
P = r(2 pi + 4)
r = P/(2 pi + 4) <= ANSWER
11. A= pi r ^2 + 4r^2 (Make r the subject)
A = r²( pi + 4)
A/( pi + 4) = r²
r = sqrt( A/( pi + 4)) <== ANSWER
12. y=x+2/x+3 (Make x the subject)
I assume this is y = (x + 2)/(x + 3).
y(x + 3) = x + 2
xy + 3x = x + 2
xy + 2x = 2
x(y + 2) = 2
x = 2/(y + 2) <== ANSWER
13. y=2-3x/x-1 (Make x the subject)
I assume this is y = (2 - 3x)/(x - 1).
y(x - 1) = 2 - 3x
xy - y = 2 - 3x
xy + 3x = 2 + y
x(y + 3) = 2 + y
x = (2 + y)/(y + 3) <== ANSWER
14. a=2+3a/b-2 (Make a the subject)
I assume this is a = (2 + 3a)/(b - 2).
a(b - 2) = 2 + 3a
ab - 2a = 2 + 3a
ab - 5a = 2
a(b - 5) = 2
a = 2/(b - 5) <== ANSWER
I hope those help!! :-)