MaxWong

\(\quad \frac{75\times 74\times73\times72\times71}{5\times4\times3\times2\times1}\\ = \frac{75}{5\times3}\times\frac{72}{4\times2}\times73\times71\times74\\ = 5\times9\times73\times71\times74\\=17259390\)

(1, -7) is a solution of infinitely many equations.

Examples: \(y=\frac{x-15}{2}\\ y=\frac{2x-23}{3}\\ y=x^2-5x-2\\ y= (x-8)(x^2+8x+64)\)

\(\frac{d^3}{d^5}=\frac{\frac{d^3}{d^3}}{\frac{d^5}{d^3}}= \frac{1}{d^2}\)

I don't get it. Is it a maths joke?

Maths, firstly, was used for counting. But for quicker counting, people invented addition and subtraction. Human beings are always greedy, and they invented multiplication and division for faster addition and subtraction. Then people started to be curious about questions like ' What is the ratio of perimeter of circle and the diameter?' and 'What is the length of the diagonal of the square?' , then they invented pi and square roots, those people, who were interested in maths questions, is now called mathematicians......

I will let the 3 vertices be A(1, 1), B(8, 1) and C(5, 5)

I will let AB be the base of the triangle.

AB = 8 - 1 = 7

The height of the triangle = 5 - 1 = 4

Area = 7 x 4 / 2 = 14

and I think the last time I logged into the forum is 9-7-2016

I mean 'more than 2 days' with 'long'

Solve for x : x = 5 - y

Solve for y : y = 5 - x 

Which one do you want? It is because I can't solve both variables with only 1 equation.

100 - 12y