Tier 1 · algebra

Slope-Int Ref

Reference card for slope and intercept formulas.

Files (1)

SLOPEINT.py432 bytes

def p(s):print(s)
def o1():
 p("=SLOPE=")
 p("m=")
 p("(y2-y1)")
 p("/(x2-x1)")
def o2():
 p("=Y-INT=")
 p("y=mx+b")
 p("b=y-mx")
 p("USE ANY PT")
def o3():
 p("=PAR/PERP=")
 p("PARALLEL:")
 p("m1=m2")
 p("PERP:")
 p("m1*m2=-1")
def menu():
 while True:
  p("=SLOPE-INT=")
  p("1:SLOPE")
  p("2:Y-INT")
  p("3:PAR/PERP")
  p("0:EXIT")
  c=input("?>")
  if c=="1":o1()
  elif c=="2":o2()
  elif c=="3":o3()
  elif c=="0":break
menu()

How to use it

Reference card for the three slope/intercept relationships you use constantly in Algebra I/II.

1:SLOPE — the slope formula m = (y2−y1)/(x2−x1).
2:Y-INT — solve y=mx+b for b using any point on the line: b = y − mx.
3:PAR/PERP — parallel lines have equal slopes; perpendicular slopes multiply to −1.
0:EXIT — leave.

Example problem

Line A has slope 2. You need the slope of a line perpendicular to A but you forget the rule.

Run SLOPEINT.
Pick 3:PAR/PERP.
Screen shows: PERP: m1*m2=-1.

Solve: m1 · m2 = −1, so m2 = −1/m1 = −1/2. The perpendicular line has slope −½. ✓

TI-84 Plus CE — try before committingoff

TI-84 Plus CE




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  Press ON to start.

Test cases (2)

ID	Inputs	Expected contains
slope-formula	1, 0	y2-y1
par-perp	3, 0	PARALLEL