How much part can sally paint in an hour ?
a ÷ 7 = a/7
And what about Steve ?
a ÷ 9 = a/9
Where, a is the total area of the room.
So, let the time taken by both of them to paint the room together be 't'
So,
t(a/7 + a/9) = a
t(9a/63 + 7a/63) = a
t(16a/63) = a
t = 63/16 ≈ 4 hr
1. You have that the circle that defines the part of the planter wall which gets watered by the sprinkler is: (x−10)²+(y+12)²<span>=36.
2. The standard form for the equation of a circle is:
(x-h)</span>²+(y-k)²=r²
(h,k) is the center point.
r is the radius.
3. Keeping this on mind, you can find the value of the radius, as below:
r²=36
r=√36
r=6 m
4. Then, the diameter of the circle is:
D=2r
D=2(6m)
D=12 m
<span>
What is the diameter, in meters, of the circular area that gets watered by the sprinkler?</span>
The answer is: 12 m
You did it right (almost, I got 21 instead of 19) but didn't finish. You need to show your discriminant is never negative.
x² + (p+1)x = 5-2p
x² + (p+1)x +(2p-5) =0
Real roots mean a positive (or at least non-negative) discriminant:
D = b² - 4ac = (p+1)² - 4(1)(2p - 5) = p² + 2p + 1 - 8p + 20
D = p² - 6p + 21
It's not totally obvious that D>0; we prove that by completing the square by noting
(p-3)² = p² - 6p + 9
so
p² - 6p = (p-3)² - 9.
D = p² - 6p + 21
D = (p-3)² - 9 + 21
D = (p-3)² + 12
Now we clearly see D>0 always because the squared term can't be negative, so D is always at least 12. We always get two distinct real roots.
terms: -5x, 4, -x, -1
like terms: 4 and -1, -5x and -x
coefficients: -5 and -1
constants: 4 and 1
(depending on your teacher, the - could not be considered part of the coeficient, meaning the coefficents would be -5 and 1, as well as just x, not -x)
Answer:
Marcus needs to buy at least twice as many pounds of apples as pounds of bananas
