First you do 150 divided by 20, which equals 7.5, so then you would do 7.5 times 6 and that equals 45 minutes. Hope that helped!
y= -4x² - 16x - 14
Take the coefficient of x² as the common factor
y = - 4(x² + 4x + 7/2)
Add (b/2)² to complete the square
y = - 4( x² + 4x + 2² - 2² + 7/2)
Complete the square
y = -4( (x + 2)² - 1/2)
Remove the bracket
y = -4(x + 2)² + 2
Answer: y = -4(x + 2)² + 2
You first work out the mean then for each number subtract the mean and square the result then work out the mean of those squared differences and take the square rot of that and you're done :)
