D = r t
384 = 640 * t
384/640 = t
.6 = t .6 of an hour
.6 hr * 60min/1 hr = 36 minutes (just in case it needs to be in minutes)
Answer:
x = 1/4
y = -1/2
z = 9/4
Step-by-step explanation:
Here we have a system of 3 equations with 3 variables:
4*x + 2*y + 1 = 1
2*x - y = 1
x + 3*y + z = 1
The first step to solve this, is to isolate one of the variables in one of the equations, let's isolate "y" in the second equation:
2*x - y = 1
2*x - 1 = y
Now that we have an expression equivalent to "y", we can replace this in the other two equations:
4*x + 2*(2*x - 1) + 1 = 1
x + 3*(2*x - 1) + z = 1
Now let's simplify these two equations:
8*x - 1 = 1
7*x - 3 + z = 1
Now, in the first equation we have only the variable x, so we can solve that equation to find the value of x:
8*x - 1 = 1
8*x = 1 + 1 = 2
x = 2/8 = 1/4
Now that we know the value of x, we can replace this in the other equation to find the value of z.
7*(1/4) -3 + z = 1
7/4 - 3 + z = 1
z = 1 + 3 - 7/4
z = 4 - 7/4
z = 16/4 - 7/4 = 9/4
z = 9/4
Now we can use the equation y = 2*x - 1 and the value of x to find the value of y:
y = 2*(1/4) - 1
y = 2/4 - 1
y = 1/2 - 1
y = -1/2
Then the solution is:
x = 1/4
y = -1/2
z = 9/4
I think because the angles are corresponding/opposite to each other u equate them to 180°
Answer: 2a^2+22a+−1
Step-by-step explanation:
Let's simplify step-by-step.
2a^2−5a+(9)(3)a−1
=2a^2+−5a+27a+−1
Combine Like Terms:
=2a^2+−5a+27a+−1
=(2a^2)+(−5a+27a)+(−1)
=2a^2+22a+−1
31a) Think of $30.90 as 100% of her bill, we first want to find 6%
To work out how much this is, we need to divide the percentage by 100 to get a multiplier (decimal)
6/100 = 0.06
Multiply 0.06 and $30.90 to get the tax
$30.90 x 0.06 = 1.854
As we can't have part of a cent, we round to the nearest 100th
If the number to the right of this value is below 5 we round down, 5 or more we round up
4 is below 5 so we round down
$1.85
31b) For the total bill, we need to add together the original and the tax
$30.90 + $1.85 = $32.75
32a) Simple Interest = PRT
This means
P x R x T
We need to multiply together the Principal, Rate and Time span
We need to turn the percentage into a decimal, so we divide by 100 like before
3.2 / 100 = 0.032
$750 x 0.032 x 6 = $144
32b) To find the account balance, we need to add the interest to the original amount
$750 + $144 = $894
