They are linear functions.
We need only two points to plotting a graph.
5.
y = -x + 6
Choose any two values of x and calculate y.
for x = 0 → y = -0 + 6 = 6 → (0, 6)
for x = 6 → y = -6 + 6 = 0 → (6, 0)
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6.
Convert the equation of line from the standard form to slope-intercept form.
y = mx + b
-15x + 10y = -60 add 15x to both sides
10y = 15x - 60 divide both sides by 10
y = 1.5x - 6
Choose any two values of x and calculate y.
for x = 0 → y = 1.5(0) - 6 = 0 - 6 = -6 → (0, -6)
for x = 4 → y = 1.5(4) - 6 = 6 - 6 = 0 → (4, 0)
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7.
x = -5
It's a vertical line
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8.
15y - 12x = -60 add 12x to both sides
15y = 12x - 60 divide both sides by 15
y = 0.8x - 4
Choose any two values of x and calculate y.
for x = 0 → y = 0.8(0) - 4 = 0 - 4 = -4 → (0, -4)
for x = 5 → y = 0.8(5) - 4 = 4 - 4 = 0 → (5, 0)