Help I will be marking brainliest!!!

Which equation represents a parabola with the focus at (0, -1) and

kow [346]

Answer:

Step-by-step explanation:

The vertex is halfway between focus and directrix, at (0,0).

The equation has the form y = ax².

Focal length p = distance between focus and vertex = 1

p = 1/|4a|

1 = 1/|4a|

|a| = ¼

The focus lies below the vertex, so the parabola opens downwards and a<0.

y = -¼x²

5 0

3 years ago

When a teacher counted her student in group 4. There were 2 students left over.When she counted them in groups of 5.She had I st

VARVARA [1.3K]

Answer:

Step-by-step explanation:

Number of students in her class = x students

x is 2 more than a multiple of 4

This means x is an even number because multiples of 4 are even and adding 2 does not change its parity.

X is also 1 more than a multiple of 5. And we know x is and even number it has to be a multiple of 5 ending in 5, not 0. So 5 + 1 is 6.

All multiples of 4 ending in six are 16, 36, 56 ..... and so on

Since there are 15 girls and lower no of boys we need to find out which number of boys are there in 16, 36, 56.

16- 15 = 1

36 - 15 = 21

And 21 is more than 15 therefore the answer is 16 students. 15 girls and 1 boy.

7 0

4 years ago

Solve for a. 1. all real numbers 2. -1 3. 0 4. no solution

Vitek1552 [10]

I think it’s all real numbers

7 0

3 years ago

Mrs. Johnson’s class sold cookies for $2.50 each and Mr. Smith’s class sold popcorn for $1.50 each. Together, the classes sold 5

sashaice [31]

Answer:

(a) Mrs. Johnson’s class sold 26 cookies, Mr. Smith’s class sold 27 popcorn.

(b) Mrs. Johnson’s class earned $\$65.$ Mr. Smith’s class earned $\$40.5.$ Hence, Mrs. Johnson’s class earned more.

(c) Mrs. Johnson’s class earned $\$24.5$ more.

Step-by-step explanation:

Let x be the number of cookies Mrs. Johnson’s class sold and y be the number of popcorn Mr. Smith’s class sold.

(a) If Mrs. Johnson’s class sold x cookies for $2.50 each, then they earn $2.50x. If Mr. Smith’s class sold y popcorn for $1.50 each, then they earn $1.50y. In total, $2.50x+$1.50y=$105.50.

Together, the classes sold 53 items, then x+y=53.

You get the system of two equations:

$\left\{\begin{array}{l}x+y=53\\ \\2.5x+1.5y=105.5\end{array}\right.$

Solve it

$\left\{\begin{array}{l}x+y=53\\ \\2.5x+1.5y=105.5\end{array}\right.\Rightarrow \left\{\begin{array}{l}x=53-y\\ \\2.5(53-y)+1.5y=105.5\end{array}\right.,$

$132.5-2.5y+1.5y=105.5,\\ \\132.5-105.5=2.5y-1.5y,\\ \\y=27,\\ \\x=53-27=26.$

(b) Mrs. Johnson’s class earned $\$2.50\cdot 26=\$65.$ Mr. Smith’s class earned $\$1.50\cdot 27=\$40.5.$ Hence, Mrs. Johnson’s class earned more.

(c) Mrs. Johnson’s class earned $\$65-\$40.5=\$24.5$ more.

8 0

3 years ago

Appreciate it if you help

Katen [24]

Answer:

y = -2.5x + 4

Step-by-step explanation:

Slope intercept form: y = mx + b

Isolate the variable y. Note the equal sign, what you do to one side, you do to the other. Do the opposite of PEMDAS. First, subtract 5x from both sides.

5x (-5x) + 2y = 8 (-5x)

2y = 8 - 5x

Next, divide 2 from both sides to isolate the y.

(2y)/2 = (8 - 5x)/2

y = (-5/2)x + (8/2)

y = -2.5x + 4

y = -2.5x + 4 is your answer.

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8 0

4 years ago