Answer:
Step-by-step explanation:
3m + 7 = - 23
we pass the -7 to the right with a positive sign
3m = -23 - 7
we perform the sum of negative numbers
3m = -30
we pass the -3 to the right to divide
m = -30/3
we perform the division
m = -10
Answer:
2.11, 2.25
Step-by-step explanation:
19/9
= 2.11
9/4
= 2.25
Hence the mistake is that both values are different as 19/9 is 2.11 and 9/4 is 2.24
![\bf \begin{array}{lccclllll} &amount(g)&\textit{\% of titanium}&\textit{grams of titanium}\\ &-----&-----&-------\\ \textit{6\% alloy}&x&0.06&0.06\cdot x\\ \textit{20\% alloy}&y&0.2&0.2\cdot y\\ ----&-----&-----&-----\\ mixture&100&0.13&100\cdot 0.13\to 13 \end{array}](https://tex.z-dn.net/?f=%5Cbf%20%5Cbegin%7Barray%7D%7Blccclllll%7D%0A%26amount%28g%29%26%5Ctextit%7B%5C%25%20of%20titanium%7D%26%5Ctextit%7Bgrams%20of%20titanium%7D%5C%5C%0A%26-----%26-----%26-------%5C%5C%0A%5Ctextit%7B6%5C%25%20alloy%7D%26x%260.06%260.06%5Ccdot%20%20x%5C%5C%0A%5Ctextit%7B20%5C%25%20alloy%7D%26y%260.2%260.2%5Ccdot%20%20y%5C%5C%0A----%26-----%26-----%26-----%5C%5C%0Amixture%26100%260.13%26100%5Ccdot%200.13%5Cto%2013%0A%5Cend%7Barray%7D)
so.. .whatever those amounts are, of "x" and "y", for the mixture,
they must add up to 100 grams, or x + y = 100
and the titanium percentage of that sum, must yield a 13 grams of titanium on those 100 grams
thus
![\bf \begin{cases} x+y=100\to y=\boxed{100-x} \\\\ 0.06x+0.2\boxed{y}=13 \end{cases}](https://tex.z-dn.net/?f=%5Cbf%20%5Cbegin%7Bcases%7D%0Ax%2By%3D100%5Cto%20y%3D%5Cboxed%7B100-x%7D%0A%5C%5C%5C%5C%0A0.06x%2B0.2%5Cboxed%7By%7D%3D13%0A%5Cend%7Bcases%7D)
do the substitution, and solve for "x",
what's "y" amount? well, y = 100 - x
Answer:
x = 15 5/6
Step-by-step explanation:
-4 1/4x-7 6/8x=-190
get a common denominator 8
-4 1/4*2/2 x - 7 6/8 x = -190
-4 2/8 x - 7 6/8 x = -190
combine like terms
-11 8/8 x = -190
-12x = -190
divide by -12
-12x/-12 = -190/-12
x = 190/12
divide top and bottom by 2
x = 95/6
change to an improper fraction
6 goes into 95 15 times with 5 left over
x = 15 5/6