All Questions +0 230469 Questions

a) Find with explanation all triplets of primes of the form (n,n+2,n+4)
b) Find five evenly spaced primes - that is, five primes forming an arithmetic progression.

Guest Jul 15, 2021

383

help asap number theory

There are two parts to this question.

(a) Simplify n choose k / n choose k-1.
This is easy for me. I can expand n choose k and n choose k-1 and simplify to get (n-k+1)/k.
(b) For some positive integer n the expansion of read more ..

Guest Jul 15, 2021

494

+165

binomial

How many ordered pairs of positive integers (m,n) satisfy lcm[m,n]=720?

please help i am stuck
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viola Jul 15, 2021

523

PLEASE help

Overnight, I've been working on some more problems to keep practicing my skills. However, I'm having some trouble with these problems:

Guest Jul 15, 2021

480

+21

Having trouble with some Trig and Complex Number Problems

Overnight, I've been working on some more problems to keep practicing my skills. However, I'm having some trouble with these problems:

read more ..

echchew Jul 15, 2021

390

+21

Having some trouble with Precalculus Problems

A park had an actual area of 5km2. Find the area, in square centimetres, of the park on the map

Scale is 1:20000

echchew Jul 15, 2021

394

Math map scale area

Alan ●●

Guest Jul 15, 2021

448

Geometry

Let triangle ABC have side lengths AB=13, AC=14, and BC=15. There are two circles located inside angle BAC which are tangent to rays AB, AC, and segment BC. Compute the distance between the centers of these two circles.

heureka ●●●

Guest Jul 15, 2021

546

help me pls thank you

A carpenter chisels a square hole of side 2 in. through a round post of radius 2 in. The axis of the hole
intersecting that of the post at right angles. Find the volume of the wood cut out.

A sphere of diameter 1.67 cm rests in a conical wine glass whose semi-vertical angle equal to 21
degrees. If the glass contains just enough wine to touch the bottom of the sphere, find the quantity of
wine in the glass.

Guest Jul 15, 2021

200

help pls thanks!

Guest Jul 15, 2021

186

help thank you!!

A trough whose ends are isosceles trapezoids is 10 m long, the lower base is 2 m, the upper base is 6
m and the depth is 4 m. The trough contains 100,000 liters of liquid. Compute the depth of the liquid.

Guest Jul 15, 2021

614

plz help

When Deb’s cat was weighed at the Vet's in June, it was 120% of its mass in March. If the cat's mass in June was 2.52 kg , what was the cat’s mass, in kilograms, in March?
Hint Example Calc

Hi, I'm trying to get better at problem-solving in math. However, I'm having trouble with these problems. Can someone please help? I attached a picture of the problems below. read more ..

Guest Jul 15, 2021

Jul 14, 2021

429

+21

Having trouble with this precalculus problem

Each solution to x^2 + 5x + 18 = 0 can be written in the form a + bi where a and b are real numbers. What is a^2 + b^2?

echchew Jul 14, 2021

371

help with algebra

I choose a random integer n between 1 and 10 inclusive. What is the probability that for the I chose, there exist no real solutions to the equation x(x + 2) = -n? Express your answer as a common fraction.

Guest Jul 14, 2021

181

help plz

Guest Jul 14, 2021

191

help geometry

The circle with center A and radius 10 and the circle with center B and radius 9 are externally tangent. A line that is externally tangent to both circles is drawn, where both circles lie on the same side of the line . This common tangent intersects line read more ..

Guest Jul 14, 2021

272

differential equations problem

The function f(x), defined for x>=0 has the following property: For any real number a>=0, the area between the graph of y=f(x) for 0<=x<=a and the graph of y=sqrt(x) is equal to the area between the same part of the graph and the y-axis. read more ..

Find the greatest integer value of b for which the expression (9x^3 + 4x^2 + 11x + 7)/(x^2 + bx + 18) has a domain of all real numbers.

Guest Jul 14, 2021

349

Domain

JKP1234567890 ●

Guest Jul 14, 2021

343

Piecewise Functions

Let
f(x) = 2x + 7 if x < -2
f(x) = -x^2 - x + 2 if x >= -2
read more ..

Let X = (3, 5), Y = (7, -11), Z = (-13, -17).

Write a point slope form equation for each of the lines XY, YZ, ZX.
Find a1 and b1 such that points P1 = (a1, 2) and P2 = (-3, b1). read more ..

Guest Jul 14, 2021

193

help

Guest Jul 14, 2021

325

Number theory

There are two number A and B. A is a 2-digit number which is a multiple of 8. B is a 2-digit number which is a multiple of 24. What is the largest possible difference between the two numbers A and B?

Three consecutive positive odd integers a, b and c satisfy b^2 - a^2 = 348 and c^2 - b^2 > 0. What is the value of c^2 - b^2?

Guest Jul 14, 2021

414

help plz

Meyer rolls two fair, ordinary dice with the numbers 1, 2, 3, 4, 5, 6 on their sides. What is the probability that both of the dice shows a square number?

Guest Jul 14, 2021

343

Probability

f(x) is a monic polynomial such that f(0)=4 and f(1)=-10. If f(x) has degree 2, what is f(x)? Express your answer in the form ax^2+bx+c, where a, b, and are real numbers.

Guest Jul 14, 2021

307

Polynomial