280 square feet is my answe
<h2>Matrix</h2>
<em><u>matrix</u></em> is a rule of writing or presenting data consisting of rows and columns in an open or closed parenthesis.
<em><u>•</u></em><em><u> </u></em><u><em>the problem above is about matrix </em><em>multiplication</em></u>
the first type of multiplication :
if k is a constant and A is a matrix, then kA can be operated by multiplying each element of matrix A by the constant k.
<em>ex </em><em>:</em><em> </em>3[-1 2 2] = [-3 6 6]
multiplication of two matrices :
the multiplication of a 1x n matrix and a n × 1 column matrix is a 1 × 1 matrix.
<em><u>the above problem using matrices of 3 × 1 and 1 × 3 size will produce a 3 × 3 </u></em><em><u>matrix</u></em><em><u>. </u></em>
<h3>Answer :</h3>
| 3 | | 9 |
3|19| [-1 -3 -5] =|57| [-1 -3 -5]
|12| |36|
| 9×(-1) 9×(-3) 9×(-5) |
= | 57×(-1) 57×(-3) 57×(-5)|
| 36×(-1) 36×(-3) 36×(-5)|
| -9 -27 -45 |
= | -57 -171 -285|
| -36 -108 -180|
I'm going out on a limb here but x is an element of the vowels
We have 20% and 70% salt solutions.
We need 9 liters of 50% salt solution.
"t" is liters of twenty % solution "s" is liters of seventy % solution
A) t + s = 9
B) .2t + .7s = (.5 * 9)
Multiplying A) by -.2
A) -.2t + -.2s = -1.8 Adding that to B)
B) .2t + .7s = (.5 * 9)
.5s = 2.7
s = 5.4 liters of 70% salt
A) t + 5.4 = 9
t = 3.6 liters of 20% salt
Source:
http://www.1728.org/mixture.htm