4. Bring all terms containing the required letter to one side of the equation. 5. Take out the required letter as a factor (if necessary). 6. Solve for the letter.
Note: Sometimes Steps 2 and 3 are easier to do before Step 1. In the following examples, the letter in red is to be written in terms of the other letters:
b = u + t b − u = t
∴ t = b − u
V = IR V
__ I = R
∴ R = V __
I
x + tz __
y = z [Get rid of the fractions. Multiply across by y.]
xy + tz = zy [Move all terms with y to the right.] tz = zy − xy [Take out a factor of y on the right.]
∴ y = tz
____ z − x = y
A − √ A = √
tz = y(z − x) [Solve for y.] tz
_______ r 2 + h 2 = 0
____ z − x
_______ r 2 + h 2 [Isolate the square root.]
A2 = r 2 + h 2 A2 − h 2 = r 2 ± √
∴ r = ± √ EXAMPLE 4
The amount of energy in joules released in a nuclear reaction is given by E = mc 2, where m is the mass of Uranium-235 in kg and c is the speed of light in m/s. Solve for c and fi nd c
