Answer:
Step-by-step explanation:
We'll call the 2 numbers x and y. Starting with the last part of that first sentence "one number is 10 times the other number" can be written, in algebraic form:
y = 10x
Now on to the first statement about the numbers: "twice their sum" is 2(x + y) and "equals their product" is = xy. Putting that all together:
2(x + y) = xy and we know that y = 10x so
2(x + 10x) = x(10x) and
and
and
x(10x - 22) = 0 so
x = 0 or 10x - 22 = 0 which makes
x equal to 
So x = 2.2 and y = 22.
Answer:
-9
Step-by-step explanation:
f(2) - f(4) / 2-4
[2²+3(2)] - [4²+3(4)] / -2
(10 - 28) / 2
= -18/2
= -9
Answer:
There are 24 nickels
Step-by-step explanation:
Let x represent the number of nickels
Let y represent the number of quarters
—————————————————————
Value Value
Type Number of of
of of each all
Coin Coin Coin Coin
—————————————————————
Nickels | x | $0.05 | $0.05x
Quarters | y | $0.25 | $0.25y
—————————————————————
Totals 28 ——— $2.20
•••••••••••••••••••••••••••••••••••••••••••••••••
The first equation comes from the “Number of coins” column.
(Number of nickels) + (Number of quarters) = (total number of coins)
Equation: x + y = 28
—————————————————————
The second equation comes from the “value of all coins” column.
(Value of all nickels) + (Value of all quarters) = (Total value of all coins)
0.05x + 0.25y = 2.20
Remove the decimals by multiplying each term by 100:
5x + 25y = 220
—————————————————————
So we have the system of equations:
{x + y = 28
{5x + 25y = 202
Solve by substitution. Solve the first equation for y:
x + y = 28
y = 28 - x
Substitute (28 - x) for y in 5x + 25y = 220
5x + 25 (28 - x) = 220
5x + 700 - 25x = 220
-20x + 700 = 220
-20x = -480
x = 24
The number of nickels is 24.
————————————————————
Substitute in y = 28 - x
y = 28 - (24)
y = 4
The number of quarters is 4.
————————————————————
Checking:
24 nickels is $1.20 and 4 quarters is $1.00
That’s 28 coins.
Indeed $1.20 + $1.00 = $2.20
————————————————————
Answer:
The correct answer is last option
surface area = 104 yd²
Step-by-step explanation:
Formula:
Surface area of cylinder = 2πr² + 2πrh
Where r is the radius and h is the height of cylinder
To find the surface area of cylinder
Here r = 4 yd and h = 9yd
Surface area = 2πr² + 2πrh = 2π * 4 * 4 + 2π *4 *9
= 32π + 72π = 104π yd²
Therefore the total surface area of given cylinder = 104π yd²
The correct answer is last option .
