Y=4x−1 Explanation: The equation of a line in slope-intercept form is. ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ∣ ∣ ∣ 2 2 y = m x + b 2 2 ∣ ∣ ∣ −−−−−−−−−−−−−−−
where m represents the slope and b, the y-intercept. Rearrange 4 x − y = 1 into this form subtract 4x from both sides. 4 x − 4 x − y = − 4 x + 1 ⇒ − y = − 4 x + 1 multiply through by -1 ⇒ y = 4 x − 1 ← in slope-intercept form
One polynomial identity that crops up often in various areas is the difference of squares identity: A2-b2=(a-b) (a+b) We meet this in the context of rationalising denominators.
