Suppose the length of the card board was x cm by x cm
After squares of 4cm was cut from the corner, the dimension for the box will be:
length=(x-8) cm
width=(x-8) cm
height=4 cm
thus the volume will be:
V=length*width*height
V=4×(x-8)×(x-8)=144
x²-16x+64=36
this can be simplified to form a quadratic equation given by:
x²-16x+28=0
solving the quadratic equation we get:
x=2 or x=14
Thus we conclude that the original dimensions was:
length=14 cm ; width=14 cm
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
————————————————————
<span> x = 34
Because
</span><span>4x + -10 + x = 180
</span><span>
-</span><span>10 + 5x = 180
</span>
Add 10 to each side <span>-10 + 10 + 5x = 180 + 10
</span>
<span>-10 + 10 + 5x = 180 + 10
</span> thn
divide each side by 5
so x=34
have a great day :)
Answer:
y=3
Step-by-step explanation:
