Answer:
D
Step-by-step explanation:
out of the choices
A) 2x-y=-2
3x+2y=-10
B) x+4y=3
2x+5y=3
C) 2x+3y=5
x-4y=-14
D) 3x+4y=15
x+y=5
only the system in D has a solution of x=5 and y=0
solve by substitution x+y=5 so x=5-y
plug into the other equation so 3(5-y)+4y=15
distribute 15-3y+4y=15 then minus 15 on both sides and combine like terms
so y=0 then put that value back into the other equation
so x+y=5 equals x+0=5 so x=5 this means the solution to the system of equations is the point (5,0)
Hope this helps! :)
2a^2+4a+1 is equivalent to 4a+4/2a*a^2/a+1
With amounts measured in gallons, let
x = amount of 65% antifreeze
y = amount of 90% antifreeze
1 gal of the 65% brand contains 0.65 gal of pure antifreeze; x gal would contain 0.65x gal. Similarly, y gal of the 90% brand contains 0.90y gal of pure antifreeze.
To obtain 120 gal of 80% antifreeze solution (which contains 0.80•120 = 96 gal of pure antifreeze), we must have
x + y = 120 … … … … … [total volume of antifreeze solution]
0.65x + 0.90y = 96 … [total volume of pure antifreeze]
Solve the first equation for y :
y = 120 - x
Substitute this into the second equation and solve for x :
0.65x + 0.90 (120 - x) = 96
0.65x + 108 - 0.90x = 96
0.25x = 12
x = 48
Solve for y :
y = 120 - 48
y = 72
<h3>Answer: $26.62 </h3>
============================
Work Shown:
P = 20 is the amount deposited
r = 0.10 is the decimal form of the 10% interest rate
n = 1 means we compound 1 time per year (annually)
t = 3 is the number of years
Plug those four values into the compound interest formula below
A = P*(1+r/n)^(n*t)
A = 20*(1+0.1/1)^(1*3)
A = 20*(1+0.1)^(3)
A = 20*(1.1)^(3)
A = 20*1.331
A = 26.62
