arrgh!! HELP?!?

Question

what's 3y+4x+65? what are the letters? ARRGH, MY MATHS SUCKS! and what's 4y+3x=71???

Answer 1

3y + 4x + 65 is an expression in terms of two variables.
4y + 3x = 71 is an equation in two unknowns.
The equation can be manipulated to get either of the unknowns in terms of the other:
y = (71 - 3x)/4
x = (71 - 4y)/3

Answer 2

I am assuming both equations are related and you are supposed to find out the value of x and y?

3y + 4x + 65 = 0 (1)
4y + 3x = 71 (2)
? Are you sure these are correct?
the (1) expression is
3y = -4x - 65 after subtracting -4x - 65 to both sides
y = -4/3 x - 65/3
From expression (2), insert the value of y
4 (-4/3x - 65/3) + 3x = 71
-16/3 x - 260/3 + 3 x = 71
Moving the x's to one side
-16/3 x + 3x = 71 + 260/3
-7/3x = 473/3
multiply both sides by -3,
7x=-473
devide both sides by 7,
x = -473/7

For y, y = -4/3x - 65/3 from earlier
y = -4/3 x (-473/7) - 65/3
you can get the answer by punching that in a calculator.

Answer 3

The first is a variable expression. The letters represent numbers. They could be anything, but maybe the paragraph before the problem told you and wanted you to finish the arithmetic.

The second is a 2 variable equation. There's an infinite set of numbers, choices for x and y, that will make the equation true. If you plot those x,y pairs on a graph, the points will all be on a straight line.

If you're halfway through the school year and still don't know what a variable is, the only thing that sucks is the vacuum between your ears. You haven't listened even to the simple things in your class and should be making plans to retake it. If you need it to graduate, which by now should be almost everywhere on the planet where there's education at all.

Answer 4

Time for a bit of elemetary algebra. It is convenient to be able to deal with quantites whose values you don't know; these can be called variables because they can change. The expressions in your question are in fact called expressions; the first one represents a number obtained by multiplying whatever number "y" represents by three, adding to that the product of whatever number "x" represents multiplied by four, and adding 65. If, for example, y were 7 and x were 5, the value would be 3*7 + 4*5 + 65, or 106. I have used the asterisk "*" to represent multiplication here; that is commony done in the computer business.