L1: x - 4y = 20
L2: 4x + y = 4
2007-05-01 08:13:40 · 4 answers · asked by Ashley H 1 in Science & Mathematics ➔ Mathematics
x - 4y = 20
x - 4y - x = - x + 20
- 4y = - x + 20
- 4y / - 4 = - x / - 4 + ( 20 / - 4)
y = 1/4x + (- 5)
y = 1/4x - 5
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4x + y = 4
4x + y - 4x = - 4x + 4
y = - 4x + 4
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L1: y = 1/4x + 5
L2 : y = - 4x + 4
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The lines are perpendicular - 4x = 1/4x is the reciprocal
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2007-05-01 08:43:56 · answer #1 · answered by SAMUEL D 7 · 0⤊ 0⤋
They are perpendicular because there slopes -4 and 1/4 are opposite inverses
2007-05-01 15:51:55 · answer #2 · answered by lass 2 · 0⤊ 0⤋
Compare their slopes!
Identical slopes â parallel
Negative inverse slopes (their product is -1) â perpendicular.
2007-05-01 15:17:16 · answer #3 · answered by Anonymous · 0⤊ 0⤋
y = x/4 - 5
y = -4x + 4
Slopes are negative reciprocals of each other.
That indicates the lines are perpendicular.
2007-05-01 15:18:34 · answer #4 · answered by MamaMia © 7 · 0⤊ 1⤋