One number is equal to two times a second number. two times the first number plus two times the second number is 24. if you let x stand for the first number and y for the second, what are the two numbers? a. x = –24, y = –12 b. x = 12, y = 6 c. x = 8, y = 4 d. x = 24, y = 12

C, x = 8 and y = 4

Step-by-step explanation:

Let's isolate y.

x = 2y

Divide both sides by 2.

x/2 = y

Now plug it in to the other equation.

2x + 2(x/2) = 24

Simplify.

2x + x = 24

Simplify.

3x = 24

Divide both sides by 3.

x = 8

Now plug x back into the original equation.

8/2 = y

Simplify.

4 = y

Therefore, the answer is C, x = 8, y = 4.

51

step-by-step explanation:

73-22=51 the   mass number minus the amount of protons gives you the amount of neutrons

hello from mrbilldoesmath!

answer:

(7 x + 6 y) (49 x^2 - 42 x y + 36 y^2)

discussion:

the trick is to recognize that 343 = 7^3 and 216 = 6^3 and, in general,

a^3 + b^3 =   (a + b) (a^2 - a b + b^2).

in our case

343x^3+216y^3   =   (7x)^3 + (6y)^3

so take a = 7x and b = 6y in the above equation to get the answer.

you,

mrb