help!
2007-06-23 02:18:00 · 5 answers · asked by mariarooster 1 in Science & Mathematics ➔ Mathematics
find y if the distance between (2,y) and (7,8) is 13
2007-06-23 02:23:30 · update #1
What is your question?
Is it to simplify and solve the equation and what has it to do with trigonometry?
13 = sqrt(5^2 + 8^2 - 16y + y^2)
13 = sqrt(89 - 16y +y^2)
169 = 89 - 16y + y^2
y^2 - 16y - 80 = 0
(y-20)(y+4) = 0
y = 20 or y = -4
2007-06-23 02:21:34 · answer #1 · answered by Anonymous · 0⤊ 0⤋
169 = 5² + (8 - y)²
(8 - y)² = 144
8 - y = ± 12
y - 8 = ±12
y = 20 , y = - 4
OR
64 - 16y + y² = 144
y² - 16y - 80 = 0
(y - 20).(y + 4) = 0
y = 20 , y = - 4
2007-06-27 05:21:47 · answer #2 · answered by Como 7 · 0⤊ 0⤋
Square both sides
13^2 = 5^2 + (8-y)^2
Recognise the 5,12,13 Pythagoran Triple.
8-y=12
y = -4
OR
8-y=-12
y=20
y is either -4 or 20
2007-06-23 09:22:55 · answer #3 · answered by gudspeling 7 · 1⤊ 0⤋
â(25 + 144) = â169 = 13
y = -4
2007-06-23 09:29:14 · answer #4 · answered by Anonymous · 0⤊ 1⤋
squaring both sides
169 = 25+(8-y)^2
144 = (8-y)^2
taking sq root of both sides we get
+-12 =8-y
y= -4 or 20
Source(s):
Sorry no trigo here
2007-06-23 09:24:14 · answer #5 · answered by sweet n simple 5 · 1⤊ 0⤋