(70/(2+4e^.2t))=20 solve for t?
820309
70= 40 + 80e^.2t\n30= 80e^.2t\n3/8 = e^.2t\nln (3/8) = .2t   \n{by equivalent form which says the log base e of e^x = x}\n\nln (3/8) /.2 = t\nt is approx. equal to -4.904146265
706256
x(rt2)x+5rt2(x^2)-25y(rty)\n=6rt2x^2-25yrty
640437
-17 +t/5 = 3\nt/5 = 3 + 17\nt/5 = 20\nt = 100\n\n(5+r)/-2 = -6\n5+r = -6 * -2\n5 + r = 12\nr = 7 \n\nor\n\n5 + r/-2 = -6\nr/-2 = -11\nr = 22
124621
x-4y=-20\n=> -4y=-x-20\n=> 4y=x+20\n=> y=x/4+5 Ans.\nThanks.
870236
Let's use elimination.\nMultiply the first equation by 4 and multiply the second equation by 3, and then add them.\n8x - 12y = -4\n9x + 12y = 24\n17x = 20\nx = 20/17\nTo find y, just replace x with 20/17 in one of the equations and solve for y.\n2(20/17) - 3y = -1\n40/17 - 3y = -1\n-3y = -1 - 40/17\n-3y = -17/17 - 40/17\n-3y = -57/17\nMultiply both sides by -1/3\ny = (-57/17)(-1/3)\ny = 19/17\nAnswer: x = 20/17 and y = 19/17 \nor you could write it as (20/17, 19/17)
893823
Use the quadratic equation \n\nt = -b + or - sqr(b^2 - 4ac)/2a\n\nyour equation is already in the form:\n\nat^2 + bt + c = 0\n\njust plug in the variables and solve for t twice
66380
You have to use the formula -\nm1s1(t3-t1)=m2s2(t2-t3)\n=>191(4.184)(30.5-25)=38s2(192-30.5)\n=>s2=191(4.184)(5.5)/((38)(161.5)\n=>s2=0.716 J/g.k
953232
Problem 1:\n\nif t=3 then 0.18t = 0.54, so\n\nAoe^-0.54 = 40, amount in 3 days.  Solve for Ao:\n\nAo = 40e^0.54 = 68.64.\n\nNote e^-x = 1/e^x (change the sign of the exponent when inverting), I divided both sides by e^-0.54 to isolate Ao.\n\nProblem 2:\n\nlog 5^(1/5) = (1/5)log 5 = (1/5) x 0.7 = 0.14.\n\nI just guessed what you meant by the second one, assuming 1/5 was an exponent.
1047159
3x+3x+2x+2x=70\n10X=70\nx= 70/10\nX=7\n\n3*7=21\n2*7=14\nthe length and width are 21,14
633469
Set h(t) = 26 and solve,\n\n26 = 11 +34t -16t^2\n\n16t^2 - 34t +15 = 0\n\nnow, factoring by parts:\n\n(16t^2 - 24t - 10t +15)\n\n8t(2t - 3) - 5(2t - 3)\n\n(8t - 5)(2t - 3) = 0\n\nSo, it passes the window at t= 5/8 and t = 3/2.
1023956
2e*2f + 16e - 4f^2 - 16f\n\n = 4ef + 16e 4f^2 - 16\n\n(use the "distributive law" of math)\n\na * ( b + c )  = ab + ac !!!!!
103938
you have to solve p such that S=D=Q.\n\nfrom S, p=Q/10 -70\n\nput that instead of p into D equation, solve for Q\n\nthen use that Q to compute p=Q/10 -70
707418
20x^2+60x + 45\n= 5(4x^2+12x + 9) \n= 5((2x)^2+2(2x)3+3^2) = 5(2x+3)^2\n\n3x^2+12x+12 = 0\n=> x^2+4x+4 = 0 (divide by 4)\n=>(x+2) ^2 = 0 or x = -2, -2 (double root)\n\n7x^2-28 =0\n= x^2 = 4\n=> x = 2 or -2\n\narea = xy = 5*2 = 10cm^2
260457
20 - - 4 = 24\nminus and minus = plus\nie\n20 - - 4 = 20 + 4 = 24
244208
let\nl= 4h - 20,\nw= 2h + 10, and\nv= l*w*h,    then\n\nv= (4h - 20)*(2h + 10)*h\nv= (8h2-200)*h\n\nv= 8h3 - 200h
747676
2C12H22O11 +24O2 ---> 24CO2 +22H2O\na)F\nb)F\nc)T\nd)F\ne)T\nf)T
664218
3(2^t)=21\n\n==> 2^t = 21/3\n==> 2^t = 7\n==> log(2^t) = log(7)\n==>t * log(2) = log(7)\n==> t = log(7)/log(2)