A
given the 2 equations
2x + y = - 2 → (1)
x + y = 5 → (2)
subtract (2) from (1) term by term to eliminate y
(2x - x ) + (y - y ) = (- 2 - 5 )
x + 0 = - 7 ⇒ x = - 7
substitute x = - 7 in either of the 2 equations and solve for y
(2) : - 7 + y = 5 ( add 7 to both sides )
y = 5 + 7 = 12 → A
The answer is 2 and negative 9
Answer:
3 nickels and 5 quarters
Step-by-step explanation:
Let n = number of nickels
q = number of quarters
q = n+2
.25q + .05n = 1.40
Using the first equation and replacing q in the second equation
.25( n+2) + .05n = 1.40
Distribute
.25n+.50 +.05n = 1.40
Combine like terms
.30n +.5 = 1.40
Subtract .5 from each side
.3n +.5-.5 = 1.40-.4
.3n = .9
Divide by .3
.3n/.3 = .9/.3
n = 3
q = n+2
q=5
I hope that 2-1 means 21.
DE + EF = DF
4x + 10 + 21 = 9x - 15
4x + 31 = 9x - 15
31 = 9x - 4x - 15
31 = 5x - 15
46 = 5x
x = 9 1/5 = 9.2
You want 9x - 15
9*9.2 - 15
82.8 - 15
67.8 <<<<< answer.
If I have given the wrong meaning to 2-1 (which could mean 1) leave another note and I will correct my work.
The answer is D 75% of the original volume is left.
