STANDARD: Algebra
LEVELS: M - MH
PURPOSE: Identifiy slope & y-intercept from both forms of equations
standard form (x = y + b)
slope / intercept form (y = mx + b)
STRATEGY: Mentally " move" one term to the other side of the equal sign to put the equation into slope / intercept form.
(y = mx+b) or (mx + b = y)
Either way is OK. It makes it easier to mentally find the slope (coefficient of x) and the y-intercept (the number without a variable) is this form.
Standard Form Equations
-7/4 x = y – 3
Use the Inverse Property to , mentally, "un-do" or "move" the -3 to the other side by putting a +3 on both sides.
-7/4 x = y – 3
+3 = +3
-7/4x +3 = y or y = -7/4x + 3
Now, see the slope / intercept form to find the coefficient of x, which is the slope; and to find the single number (no variable) which is the y-intercept.
So, m = -7/4 and y-intercept = +3
Slope / Intercept Form Equations
y = 1/2x – 1
The slope is the coefficient of x or 1/2, and the y-intercept is the single number (no variable) or -1
So, m = 1/2 and y-intercept = -1
Other Equations
-x = y
If you use the identity property, add zero (+ 0), the equation doesn't change. It can be seen as
y = -x + 0.
So, -1 is the Slope & O is the y-intercept.
So, m = -1 and y-intercept = 0
DIRECTIONS: Notice the check mark on each slide, and write EITHER the slope or y-intercept before the slide changes. WRITE ANSWERS ON PAPER - promotes a good "math work ethic of using mental math with paper & pencil, as well as, caluclators.
HINT: Read the addition or subtraction sign as + or - for the number behind it.Then, "put the opposite" on both sides.
