Can someone help me please

Y = x^2+ 7x - 5 can be written in the form y = (x + a)^2+b

BARSIC [14]

Answer:

see explanation

Step-by-step explanation:

The equation of a parabola in vertex form is

y = (x - h)² + k (h, k) are the coordinates of the vertex

Given y = x² + 7x - 5

To express in vertex form use the method of completing the square

add/subtract ( half the coefficient of the x- term )²

y = x² + 2( $\frac{7}{2}$ )x + $\frac{49}{4}$ - $\frac{49}{4}$ - 5

y = (x + $\frac{7}{2}$ )² - $\frac{49}{4}$ - $\frac{20}{4}$

y = (x + $\frac{7}{2}$ )² - $\frac{69}{4}$

Hence

a = $\frac{7}{2}$ and b = - $\frac{69}{4}$

8 0

3 years ago

Ann is 5 feet 3 inches tall. To find the height of a lamppost, she measured her shadow to be 8 feet 9 inches and the lamppost’s

Makovka662 [10]

Answer: The lamppost is 7 feet 2 inches

Step-by-step explanation: If Ann measured her own height and her shadow, then what she used is a ratio between both measurements. If she can measure the shadow of the lamppost, then she can use the same ratio of her height and it’s shadow to derive the correct measurement of the lamppost.

If Ann’s height was measured as 5 feet 3 inches, and her shadow was 8 feet 9 inches, the ratio between them can be expressed as 3:5.

Reduce both dimensions to the same unit, that is, inches. (Remember 12 inches = 1 foot)

Ratio = 63/105

Reduce to the least fraction

Ratio = 3/5

If the height of the lamppost is H, then

H/144 = 3/5

H = (144 x3)/5

H = 86.4

Therefore the lamppost is approximately 86 inches, that is 7 feet and 2 inches tall.

5 0

3 years ago

PLEASE HELP‼️‼️Drag the expression that is the most reasonable measurement for each object.

Afina-wow [57]

Answer:

A. Length of a Tour Bus ↔ #2. 1.1 × 10¹ meters

B. Width of an apple ↔ #3. 4 × 10⁰ centimeters

C. Distance from Earth to a Satellite ↔ #6. 8 × 10² kilometers

D. Thickness of a human hair ↔ #5. 9 × 10¹ micrometers

Explanation:

A. Length of a tour bus.

The length of a tour bus should be measured in meters. It sure is way less than 1 kilometer and way more than a few centimeters. It could be about some meters, more than 5 meters, may be between 10 meters and 15 meters.

The measurement in the box # 2. is 1.1 × 10¹ meters, which is equivalent to 1.1 × 10meters = 11 meters. Thus, this is a reasonable length.

B. Width of an apple.

The most appropiate unit to measure the width of an apple should be centimer. It certanly is shorter than 1 meter and bigger than 1 mm.

The width of an apple could be, more or less, around 8 centimeters. The only measurement in the boxes that is in that order is that in the box #3., 4 × 10⁰ centimeters, because 10⁰ = 1, so 4 × 10⁰ = 4 × 1 = 4centimeters.

C. Distance from Earth to a Satellite

The distance from Earth to a satellite should be measured in kilometers.

You can find in the internet that the distances of the satellites are between 700 kilometers and 36,000 kilometers.

The number in the box #1 is too big, in the order of ten trillions of kilometers, because one trillion is 10¹²; thus that is notreasonalbe (too big).

The number in the box #6 is 8 × 10² kilometers, which is equal to 8 × 100 = 800 kilometers.

Thus, 8 × 10² kilometers (box #6) is the most reasonable measurement for the distance from Earth to a Satellite

D. Thickness of a human hair

Of course, kilometers, meters, centimeters and even milimeters are units too big to measure the thickness of a human hair.

One micrometer is 10⁻⁶ meters or 10⁻³ milimeters.

In the internet you can find that diameter of the humar hairis in the range from 17 micrometers to 181 micrometers.

The measurement in the box #5. is 9 × 10¹ micrometers, which is equivalent to 9 × 10 = 90 micrometers.

Thus, 9 × 10¹ micrometers is the most reasonable measurement fot the thickness of a human hair.