I don’t understand what you’re saying ?
I am assuming you wrote the problem wrong. Is it a^2?
A^2 -4A-21=0
(A-7)(A+3)=0
A=7 A=-3, ignore the negative number because it doesn't make sense if you plug in for a.
length=a+3=7+3=10
Width=7=a
Answer:
D. 0.925x + 0.88y = 0.91(x + y)
Step-by-step explanation:
The important point to remember is that the total mass of pure silver is the same on each side of the equation.
0.925x = mass of pure silver in first alloy
0.88 y = mass of pure silver in second alloy
The final alloy has a mass of (x + y) g and is 91 % pure silver, so
0.925x + 0.88y = 0.91(x + y)
B is the answer i'm positive
