All categories

3 years ago

Can someone please help me Factor 4x^2 - 81

Mathematics

2 answers:

Oduvanchick [21]3 years ago

6 0

The answer is (2x-9)(2x+9)

4x^2-81
2^2 x^2-9^2
(2x)^2-9^2
(2x-9)(2x+9)

Vsevolod [243]3 years ago

3 0

Answer:

(2x-9)(2x+9)

Step-by-step explanation:

This is a difference of squares because it can be written as (2x)^2-9^2

The formula for factoring a difference of squares is a^2-b^2=(a-b)(a+b)

So replace a with 2x and b with 9 giving us

4x^2-81=(2x-9)(2x+9)

You might be interested in

12(4^3−6⋅3^2) solve please fast

Marrrta [24]

The answer is 291.72

3 0

2 years ago

Read 2 more answers

10 + 14x - 18 = 16x + 22 -8x

Grace [21]

If looking for x:

x=5

8 0

2 years ago

Read 2 more answers

A car has mass 1500 kg and is traveling at a speed of 35 miles/hour. what is its kinetic energy in joules? (Be sure to convert m

photoshop1234 [79]

Answer:

Factor by which kinetic energy increase = 4 times

Step-by-step explanation:

Given,

Mass of the car, v1 = 1500 kg

initial speed of car = 35 miles/h

$=\dfrac{35\times 1609.34}{3600}\ m/s$

= 15.64 m/s

Initial kinetic energy of the car is given by,

$k_1\ =\ \dfrac{1}{2}.m.v_1^2$

$=\ \dfrac{1}{2}\times 1500\times (15.64)^2\ joule$

= 183606.46 J

Final velocity of car v2 = 70 miles/hour

$=\dfrac{70\times 1609.34}{3600}$

= 31.29 m/s

So, final kinetic energy of car is given by

$k_2\ =\ \dfrac{1}{2}.m.v_2^2$

$=\ \dfrac{1}{2}\times 1500\times (31.29)^2$

= 734425.84 J

Now, the ratio of final to initial kinetic energy can be given by,

$\dfrac{k_2}{k_1}=\ \dfrac{734425.84}{183606.46}$

$=>\ k_2\ =\ 4k_1$

Hence, the kinetic energy will increase by 4 times.

7 0

2 years ago

Given= 3a + 5 = 17

choli [55]

Answer:

a=4

Step-by-step explanation:

you subtract the 5 from both sides and then you divide the 3 into the three and then you have 4

5 0

3 years ago

Read 2 more answers

Last year, the enrollment at Brown Middle School was 900 students. This year, the enrollment is 720 students. Which of the follo

Oxana [17]

I think it was decreased by 20% it by chance might be wrong but tell me if im right

6 0

2 years ago

Read 2 more answers