maths problem, helpppp:)!!!!?
when a number is decreased by 7 and this result is divided by the sum of the number and 11, the answer is -3/4. find the number
how do i write out the formula for that
when a number is decreased by 7 and this result is divided by the sum of the number and 11, the answer is -3/4. find the number
how do i write out the formula for that
Comments
(x - 7) / (x + 11) = -3/4
4 (x - 7) = -3 (x + 11)
4x - 28 = -3x - 33
4x + 3x - 28 + 33 = 0
7x + 5 = 0
x = -5/7
Let the number be N
N is decreased by 7 and this result is divided by the sum of the number and 11, the answer is -3/4. Therefore:
. .N – 7 . . . . 3
––––––– = - –– . . . . . . . . . <- cross multiply
.N + 11 . . . . 4
(N – 7)(4) = -3(N + 11)
4N – 28 = -3N – 33 . . . . . . <- rearrange
4N + 3N = -33 + 28
7N = -5 . . . . . . . . . . . . . . .<- divide both sides by 7
. . . . .5
N = - ––
. . . . .7
Done
Let the number be x
number is decreased by 7, so, x-7
sum of the number and 11 = x+11
x-7 is divided by x+11, the answer is -3/4
(x-7)/(x+11) = -3/4 This is the formula
4x-28 = -3x - 33
4x+3x = -33 +28
7x = -5
x= -5/7
the number is -5/7
let n be the number
(n-7)/(n+11) = -3/4
work backwards, start with -3/4, and say the number you are looking for is x
therefore, -3/4= (x-7)/(x+11)
hope that helps you a bit
Denote the width in cm by technique of w then the with width x length = section (the position l=length) we've wcm x (w+4)cm = 26cm^2 => w^2 + 4w = 26 ('Dividing' for the length of by technique of cmxcm and increasing) => w^2 + 4w - 26 = 0 making use of the nicely commonly used formula for fixing a^2 + bx + c = 0 ie x = (-b +/- sqrt(b^2 - 4ac))/2a with a = a million, b = 4 and c = -26 and x = w, we've w = (-4 +/- sqrt(4^2 - 4.a million.(-26)) / 2 = (-4 +/- sqrt(16 + 104)) / 2 = (-4 +/- sqrt(one hundred twenty)) / 2 = (-4 +/- 2sqrt(30))/2 = -2 + sqrt(30) or = -2 - sqrt(30) because the width w must be constructive, the in elementary words wise answer is w = (-2 + sqrt(30)) cm which makes l = (2 + sqrt(30)) cm (l = w+4, undergo in concepts) i will allow you examine the outcomes for your self.
equation is
(x-7) / (x+11) = -3/4
so 4x - 28 = -3x -33
7x = -5
x= -5/7
it might be this but im not sure
(x-7)
------------- = -3/4
(y+z=11)
you should start learning math