Answer: -3 and 5
<u>Step-by-step explanation:</u>
Let x represent the 1st digit and y represent the 2nd digit. Then,
Eq 1: 2x + 3y = 9 → 3(2x + 3y = 9) → 6x + 9y = 27
Eq 2: 3x + 2y = 1 → -2(3x + 2y = 1) → <u>-6x - 4y = -2</u>
5y = 25
y = 5
Substitute y = 5 into either of the original equations to solve for x:
2x + 3y = 9
2x + 3(5) = 9
2x + 15 = 9
2x = -6
x = -3
Check (using the other original equation):
3x + 2y = 1
3(-3) + 2(5) = 1
-9 + 10 = 1
-1 = 1 
Answer:
C
Step-by-step explanation:
The substance in the second beaker must have lost heat for it to solidify
Answer:
D
Step-by-step explanation:
3(2x-2)+5x
11x-6
It is asking you to find the sum of k^2 - 1 from k=1 to k=4. Since that is only 4 numbers, calculating the sum by hand wouldn’t be that bad.
(1^2 - 1) + (2^2 - 1) + (3^2 - 1) + (4^2 - 1) = 26
The easier way to find the sum is to use a few simple formulas.
When we have a term that is just a constant c, the formula is c*n.
When we have a variable k, the formula is k*n*(n+1)/2.
When we have a squared variable, the formula is k*n*(n+1)*(2n+1)/6.
In this case, we have a squared variable k^2 and a constant of -1.
So plug in n=4 to the formulas:
4*5*9/6 - 1*4 = 26
The answer is 26
Let t represent "total price." Then 0.20t = $1600, and t = $1600/0.20 =
$8000 (answer)
