Let first number = X and 2nd number = Y
Equation 1: 5X + 8Y = -13
Equation 2: 5X + 10Y = -15
Multiply equation 1 by -1 to get: -5X + -8Y = 13
Now add the 2 equations together:
-5X + 5X = 0
-8Y + 10Y = 2Y
13 + -15 = -2
The total of the 2 equations is 2Y = -2
divide both sides by 2 to solve for Y
Y = -2 / 2
Y = -1
Now we know the 2nd number is -1, so replace Y in the 1st equation and solve for X
5X +8(-1) = -13
5x + -8 = -13
Add 8 to both sides:
5x = -5
Divide both sides by 5 to get x
X = -5 / 5
X = -1
Both numbers are -1
To check replace X and Y with -1 and solve:
1st equation: 5(-1) +8(-1) = -5 + -8 = -13 TRUE
2nd equation: 5(-1) +10(-1) = -5 + -10 = -15 TRUE
Both numbers are -1
Word the problem so it helps you with the double number line like this:
Question:
If 1/6 mile of a fence is completed each hour how long will it be in 4 hours?
Then use the double line:
1/6-----miles(1/6*4)------X Length X=1/6*4
I X= 1/6*4/1
I X= 4/6 ≈2/3 miles
1-------hours--------------4 Time
Here is a video that might help with your homework a lot :) Good luck
https://www.youtube.com/watch?v=89VhAPhvNcA
Normalcdf(-10,000, 0.18, 0.20, 0.025) = ~ 0.212
-10,000 is our lower boundary. 0.18 is the upper boundary, which represents 45/250 red candies. 0.20 is the sample mean, which is the same as the population proportion. 0.025 is the standard deviation of the sample proportion.
Earnings: $2900
Expenditure on food: $290
Percentage expenditure on food = Expenditure on food / Earnings times 100
= $290/$2900 * 100 = 10%
Step-by-step explanation:
so, it is a quadratic equation :
-3x² + 30x - 90 = 0
the first thing we can do is divide by 3
-x² + 10x - 30 = 0
remember, the formula to solve and find the 2 solutions is
x = (-b ± sqrt(b² - 4ac))/(2a)
in our case here
a = -1
b = 10
c = -30
x = (-10 ± sqrt(100 - 4×-1×-30))/-2 =
= (-10 ± sqrt(100 - 120))/-2 = (-10 ± sqrt(-20))/-2 =
= (-10 ± sqrt(4×5)i)/-2 = (-10 ± 2×sqrt(5)i)/-2 =
= 5 ± -sqrt(5)i
x1 = 5 - sqrt(5)i
x2 = 5 + sqrt(5)i
remember, i = sqrt(-1), a complex number.
