Answer:
Sam is 12, sam's brother is 19, and sam's mom is 32.
Step-by-step explanation:
First the equation you need to use is S+7+S+3S-4=63(the variable s represents Sam), you combine the like terms which then equals 5S+3=63, then you use inverse operations. Subtract 3 on both sides, 5S=60, then you divide on both sides which equals S equals 12. Then you just plug in the number, S is Sam which means Sam's 12. Then 12+7 which is 19, Sam's brother. Then 3 times 12 minus 4 is 32. And if you check to make sure, 12+19+32 does equal 63.
For this case we have the following system of equations:

We can write a system of equivalent equations.
For this, it is enough to multiply one of the two equations by a scalar.
Multiplying the equation 1 by 2, we have:

Therefore, the new system of equations is:

Answer:
A system that is equivalent is:
D) 
Correct formula is y = kx, where k is the "constant of proportionality."
If y = 9 when x = 2, then 9 = k(2), or k = 9/2.
Then y = (9/2)x.
If x = 3, y = (9/2)(3) = 27/2 (answer)
The answer is 65 degrees because there are 180 degrees in a triangle and the triangle isosceles and 130 (because 50 degrees minus 180 = 130) divided by 2 is 65. Youre welcome
:D