x-Intercept vs. y-Intercept
The y-intercept of y = x + 2
2 or (0,2)
See #41 in the e-Textbook. (p.167)
x-axis, y-axis, & origin symmetry
What form is the equation y-2 = 3(x+4) in?
Point-slope
y = 2x - 3
y = 2x + 4
Parallel
y = k/x
Inverse variation
The x-intercept of y = x + 2
-2 or (-2,0)
See #43 in the e-Textbook. (p.167)
y-axis symmetry
What form is the equation y = 2x + 3 in?
Slope-intercept
y = 4x + 7
y = -1/4x - 2
Perpendicular
y = kx
Direct variation
The y-intercept of y = -x2 + 4
4 or (0,4)
See #45 in the e-Textbook. (p.167)
x-axis symmetry
What form is the equation -x + 3y = 6 in?
General
y = 4x + 5
y = -4x + 2
Neither
Formula for when y varies directly with x; with y = 2 when x = 10
y = (1/5)x
The x-intercept of y = 3x - 9
3 or (3,0)
See #47 in the e-Textbook. (p.167)
origin symmetry
What form is the equation y-1/2 = 2(x+3/4) in?
Point-slope
y = 5x + 10
y = 1/5x - 3
Neither
Formula for when y varies inversely with sqrt(x); with y = 4 when x = 9
y = 12/sqrt(x)
The x-intercepts of 4x2 + y = 4
-1 & 1 or (-1, 0) & (1, 0)
See #49 in the e-Textbook. (p.167)
no symmetry
What form is the equation (1/2)y = x - 1 in?
It isn't.
-6x + y = 1
-1/3 = 2x - 1/3y
Same
Formula for when M varies directly with the square of d and inversely with the square root of x; with M = 24 when x = 9 and d = 4.
M = (9d^2)/(2sqrt(x))