Let the 3-digit palindrome be 101a+10b. a+a+ab=8+b, so 2a+ab-b=8.
2a+b(a-1)=8; b=2(4-a)/(a-1). From this we know that a > 1. And we know 4-a > 0 so a < 4.
This limits a to 2 and 3 which make b=4 and 1.
The palindromes are 242 and 313.
Answer:
The size of the scale model is 60 centimeters.
Step-by-step explanation:
Given that the length of a boat is 10.8 m, and Boris buys a scale model of the boat whose ratio is 1 to 18, to determine the length of the scale model of the boat in centimeters the following calculation must be performed:
1m = 100cm
10.8 m = (10.8 x 100) = 1080 cm
1080/18 = X
60 = X
Therefore, the size of the scale model is 60 centimeters.
Answer:
Cory bought 6.47 gallons
rate of change is $2.78 per gallon
Step-by-step explanation:
cost of gas per gallon = $2.78
it means that if one buy 1 gallon he will have to pay $2.78 and similary for each increase in 1 gallon of gallon gas he will have to pay $2.78.
Thus, rate of change is cost of gas per gallon as cost to buy gas changes with the change in quantity of gallon.
Let the quantity of gas bought be x gallon.
Total cost for x gallons = cost of gas per gallon*x = 2.78x
Given that total money paid by him is $18
2.78x = 18
x = 18/2.78 = 6.47
Thus, Cory bought 6.47 gallons
rate of change is $2.78 per gallon
ANSWER
x = ±1 and y = -4.
Either x = +1 or x = -1 will work
EXPLANATION
If -3 + ix²y and x² + y + 4i are complex conjugates, then one of them can be written in the form a + bi and the other in the form a - bi. In other words, between conjugates, the imaginary parts are same in absolute value but different in sign (b and -b). The real parts are the same
For -3 + ix²y
⇒ real part: -3
⇒ imaginary part: x²y
For x² + y + 4i
⇒ real part: x² + y (since x, y are real numbers)
⇒ imaginary part: 4
Therefore, for the two expressions to be conjugates, we must satisfy the two conditions.
Condition 1: Imaginary parts are same in absolute value but different in sign. We can set the imaginary part of -3 + ix²y to be the negative imaginary part of x² + y + 4i so that the
x²y = -4 ... (I)
Condition 2: Real parts are the same
x² + y = -3 ... (II)
We have a system of equations since both conditions must be satisfied
x²y = -4 ... (I)
x² + y = -3 ... (II)
We can rearrange equation (II) so that we have
y = -3 - x² ... (II)
Substituting into equation (I)
x²y = -4 ... (I)
x²(-3 - x²) = -4
-3x² - x⁴ = -4
x⁴ + 3x² - 4 = 0
(x² + 4)(x² - 1) = 0
(x² + 4)(x-1)(x+1) = 0
Therefore, x = ±1.
Leave alone (x² + 4) as it gives no real solutions.
Solve for y:
y = -3 - x² ... (II)
y = -3 - (±1)²
y = -3 - 1
y = -4
So x = ±1 and y = -4. We can confirm this results in conjugates by substituting into the expressions:
-3 + ix²y
= -3 + i(±1)²(-4)
= -3 - 4i
x² + y + 4i
= (±1)² - 4 + 4i
= 1 - 4 + 4i
= -3 + 4i
They result in conjugates
We know that
scale factor=1 in/7.5 ft
scale factor=measurements on the blueprint/measurements <span> in the actual
</span>measurements on the blueprint=[measurements in the actual*scale factor]
so
for 18 ft
measurements on the blueprint=[18 ft*(1 in/7.5 ft)-----> 2.4 in
for 16 ft
measurements on the blueprint=[16 ft*(1 in/7.5 ft)-----> 2.1 in
the dimensions on the blueprint are
2.4 in x 2.1 in
