Rearranging Equations Rearranging equations is based upon inverse

Rearranging Equations Rearranging equations is based upon inverse functions The four mathematical operations are in pairs: + , - Add and subtract operations are opposite to each other (inverse functions) × , ÷ multiply and divide operations are opposite to each other (inverse functions)

Rearranging Equations The basic principal for rearranging equations is to look at the operation that applies to a number or variable apply the inverse function to move it to the other side of the equation Example: x+3=y to move the 3 to the other side of the ‘=‘ apply the inverse function. The function is ‘+’, so the inverse function is ‘-’ x + 3 = y-

Rearranging Equations Example: 3 x = y to move the 3 to the other side of the ‘=‘ apply the inverse function. The function is ‘×’, so the inverse function is ‘÷’ 3 × x = _y Rearrange this equation to make a the subject of the formula ×c ÷ 3 3 a = b c to have a on its own c and 3 need to be on the other side of the ‘=‘ apply the inverse functions. 3 a = b c Writing the equation like this with a = something is called making a the subject of the formula

Rearranging Equations To summarise: Multiply on one side of the equation goes to divide on the other side xy = a b Divide on one side of the equation goes to multiply on the other side xy = a b Add on one side of the equation goes to subtract on the other side x + 3 = y. Subtract on one side of the equation goes to add on the other side x - 3 = y+

Rearranging Equations Now try these: Rearrange these to make y the subject of the formula 1. a + y = b y=b-a 2. y – c = d y=d+c 3. xy = z y=z x 4. e + 2 y = f y=f-e 2 y = m – 2 l 5 y=h+i 3 5. 2 l + 5 y = m 6. 3 y = h + i