Questions on Algebra: Linear Algebra (NOT Linear Equations) answered by real tutors!

Tutors Answer Your Questions about Linear Algebra (FREE)

Question 28699: The relationship between the air temperatur t (in degrees Fahrenheit) and the altitude h ( in feet above sea level) is approcimately linear. At 1000 ft, the temperature is 60*. At 5000ft the temperature is 42*. Express t in therms of h. Use proper or improper fractions or exact decimals only no decimal approcimations.
Click here to see answer by josmiceli(19441)

Question 28706: use factoring to solve the following equations:
9x^2-16=0
i tried (3x-4)(3x-4) but this is wrong. then I thought about using the square root property, but the instructions say factoring.
Click here to see answer by longjonsilver(2297)

Question 28622: 5(y-2)-10=55

Click here to see answer by emmychan(11)

Question 28841: i need help with graphing linear equations
x+y=7
-x+y=6
-x+5y=5
y=-2x+7
Click here to see answer by elima(1433)

Question 28969: use completing the square to find the vertex of the quadratic function
y=-2x^2+16x+4
This is what i tried
y=-2(x^2-8x)+ 4
Y= -2(x-4)^2 +16-16+4
Y=-2(x-4)^2-12
vertex= (-4,-12) the answer is supposed to be vertex= (4,36)
Thanks for the help in advance
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29122: Solve the system.
x + 2y = –15
–2x + 4y = 6

Click here to see answer by sdmmadam@yahoo.com(530)

Question 29229: can someone show me how to solve by addition method...
2x=2-y
3x+y=-1
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29242: 0 = 5(x^3) + 10 + 10(x^2)
solve for x? or factor?
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29326: a-6/12=a-2/12
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29238: Let V be the plane 6x1 + 4x2 - 2x3 = 0 in R^3 and let x= (6 -2 4)
a) find the orthogonal decomposition of x with respect to V
b) find the point in V which is closest to x
Click here to see answer by venugopalramana(3286)

Question 29300: 0 = 5(x^3) + 10 + 10(x^2)
solve for x? or factor?
Click here to see answer by longjonsilver(2297)

Question 29237: how do i prove W^(perpendicular sign) is a subspace of R^n
Click here to see answer by venugopalramana(3286)

Question 29316: x+y+z=-7
2x+5y+2z=-26
-x+9y-3z=-21
what are the variables?
Click here to see answer by elima(1433)

Question 29774: Solve for x to four decimal places: e^2x =3
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29816: If f(x) =x^3 and g (x) = -6+3x, find g(f(x)).
Click here to see answer by Earlsdon(6294)

Question 29815: Write the equation 4^3=64 in logarithmic form
Click here to see answer by Cintchr(481)

Question 29820: Evaluate: log[3]243
PlEaSe HeLp
Click here to see answer by Cintchr(481)

Question 29822: Write an exponential form: t=log[99^s]
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29814: Let f(x) = 9-x^2, g(x) = 3-x. Find (f+g) (x).
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29817: I am stummped!
let f(x)=9-x^2, g(x)=3-x. Find (f-g) (x).
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29813: Given f(x) = x^3 and g(x) = 3+6x^2, find (g o f) (x).

Click here to see answer by sdmmadam@yahoo.com(530)

Question 29824: Write as single logarithm: 2log[b]^x-7log[b]y
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29839: I have to solve this proof but dont understand it all.
Here it is: Let v and w be independent column vectors in R^3, and let A be an invertible 3X3 matrix.Prove that the vectors Av and Aw are independent.
Click here to see answer by khwang(438)

Question 29823: Express in terms of logarithms of x, y, and z:
log [a] 7xy^5/ [z]^4
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29818: Find the equation of the inverse of f(x) = 7x+3/8
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29819: Solve 1/4 =8^5x-4

Click here to see answer by shyamsundhar(3)

Question 29872: Solve: log[8](3x+2)=4
Thanks
Click here to see answer by jb007mi6(53)

Question 29873: Question:
Given log[10]3=S and log[10]11=T, find log[10]33
Here are the possible answers:
S+T
ST
10^st
10^s+t
Click here to see answer by jb007mi6(53)

Question 29868: Given f(x) =x^3 and g (x) = 3+6x^2, find (g o f) (x).
Here are the possible answers:
a. none of these
b. 3+6x^2/x^3
c. 3+6x^6
d. 3+6x^2
Thanks for helping
Click here to see answer by jb007mi6(53)

Question 29869: Let f(x)=9-x^2, g(x)=3-x. Find (f+g) (x).
Here are my four choices:
(1) -x^2-x+12
(2) 3+x
(3) -x^2+x+6
(4) x^3=3x^2-9x+27
Thanks!
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29871: Express in terms of logarithms of x, y, and z: log[a] 7xy^5/ z^4
Possible answers:
(1) 35+log[a]xy-4loga^z
(2) log[a]7+log[a]x+5log[a]y-4log[a]z
(3)log[a]7+log[a]x+5log[a]y/ 4log[a]z
(4) 7+log[a]x+5log[a]y-4log[a]z
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29870: Question: Solve 1/4=8^5x-4
POssible Four Answers:
(1) 2/15
(2) 2/3
(3) 2/5
(4) 14/15
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29867: Determine the domain of the function h(x) = 3x/ x(x^2-81).
Thanks!
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29821: Determine the domain of the function h(x)= 3x/x(x^2-81)
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29879: Find all real solutions of the following equation:log[4]x+log [4] (x+12) = 3
Here are the possible solutions:
(1) x=12
(2) x=4
(3) x= 16,12
(d) none of these

Click here to see answer by Cintchr(481)

Question 29494: Let a be a fixed vector in R^3, and define W to be the subset of R^3 given by
W={x: a^Tx=0}. Provce that W is a subspace of R^3.
Click here to see answer by khwang(438)

Question 29491: If U and V are subsets of Rn,then the set U+V is defined by
U+V={ x:x=u+v, u in U and v in V}.
Prove that if U and V are subspaces of Rn, then U+V is a subspace of Rn.
Click here to see answer by khwang(438)

Question 29866: QUestion: The number of bacteris present in a culture after t minutes is given as B=10e^ky. If thre are 7212 bacteria present after 11 minutes, find k.
The possible answers are:
72.39
0.658
6.581
0.598
Thanks for your help
Click here to see answer by ikdeep(226)

Question 29926: Given f(x)=x^3 and g(x) = 3+6x^2, find (g o f) (x)
Answers to choose from:
(a) 3+6x^2/x^3
(b) 3+6x^2/x^3
(c) 3+6x^6
(d) 3+6x^2
Please help!
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29925: Please help.
Question: Find the equation of the inverse of f(x)=7x+3/8
Solutions to Choose From:
(a) f^1(x)=8x+3/7
(b) f^1 (x)=8/7x+3
(c) f^1 (x) = 7x-8
(d) f^1 (x) = 8x-3/7
Click here to see answer by sdmmadam@yahoo.com(530)

Question 29812: The number of bacteria present in a culture after t minutes is given as B = 10e^kt. If there are 7212 bacteria resent after 11 minutes, kind k.
Click here to see answer by Fermat(136)

Question 29958: 3(2x-1)=27
Use the distributive Property!
3(2x)= 6x and 3(-1) = -3
so 6x-(-3)=27
6x+3=27 Now you must get the variable by itself on one side, so subtract 3 from both sides which will get you
6x+3-3=27-3 the +3-3 cancel eachother out, and 27-3 is 24.
6x=24 Now you must solve for the x variable, so you divide both sides by 6, which will give you 6x/6=24/6
The 6's cancel out, which leaves x on the left side, and 24 divided by 6 is 4, Hence, x=4.
Click here to see answer by ZachEdmo4590(2)

Question 29957: I AM SUPPOSE TO FIND THE SOLUTION TO THIS PROBLEM:
-3X + Y= -18; 3X-Y= -16
THIS IS WHAT I GOT :
THERE IS NO SOLUTION (4.44,5.22)
Click here to see answer by sdmmadam@yahoo.com(530)

Older solutions: 1..45, 46..90, 91..135, 136..180, 181..225, 226..270, 271..315, 316..360, 361..405, 406..450, 451..495, 496..540, 541..585, 586..630, 631..675, 676..720, 721..765, 766..810, 811..855, 856..900, 901..945, 946..990, 991..1035, 1036..1080, 1081..1125, 1126..1170, 1171..1215, 1216..1260, 1261..1305, 1306..1350, 1351..1395, 1396..1440, 1441..1485, 1486..1530, 1531..1575, 1576..1620, 1621..1665, 1666..1710, 1711..1755, 1756..1800, 1801..1845, 1846..1890, 1891..1935, 1936..1980, 1981..2025, 2026..2070, 2071..2115, 2116..2160, 2161..2205, 2206..2250, 2251..2295, 2296..2340, 2341..2385, 2386..2430, 2431..2475, 2476..2520, 2521..2565, 2566..2610, 2611..2655, 2656..2700, 2701..2745, 2746..2790, 2791..2835, 2836..2880, 2881..2925, 2926..2970, 2971..3015, 3016..3060, 3061..3105, 3106..3150, 3151..3195, 3196..3240, 3241..3285, 3286..3330, 3331..3375, 3376..3420, 3421..3465, 3466..3510, 3511..3555, 3556..3600, 3601..3645, 3646..3690, 3691..3735, 3736..3780, 3781..3825, 3826..3870, 3871..3915, 3916..3960, 3961..4005, 4006..4050, 4051..4095, 4096..4140, 4141..4185, 4186..4230, 4231..4275, 4276..4320, 4321..4365, 4366..4410, 4411..4455, 4456..4500, 4501..4545, 4546..4590, 4591..4635, 4636..4680, 4681..4725, 4726..4770, 4771..4815, 4816..4860, 4861..4905, 4906..4950, 4951..4995, 4996..5040, 5041..5085, 5086..5130, 5131..5175, 5176..5220, 5221..5265, 5266..5310, 5311..5355, 5356..5400, 5401..5445, 5446..5490, 5491..5535, 5536..5580, 5581..5625, 5626..5670, 5671..5715, 5716..5760