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Answer:
Alexander is incorrect because the expressions are not equivalent.
Step-by-step explanation:
If the expression is evaluated for any value of x, y; the result will not be same.
For instance, let assume x = 1 and y = 2
3x + 4y = 3 + 4 = 7
(3)(4) + xy = (3)(4) + (1 * 2) = 12 + 2 = 14
So, the expressions are not the same and Alexander is incorrect.
Answer:
The three unknown angles X, Y , and Z are:
X = 40, Y = 20, and Z = 120
Step-by-step explanation:
Let's name X the measure of the first angle, Y the measure of the second one, and Z that of the third one.
Then we can create the following equations:
X = 2 Y
Z = 100 + Y
and
X + Y + Z = 180
So we use the first equation and the second one to substitute for the variable X and Z in the thrid equation:
2 Y + Y + (100 + Y) = 180
4 Y + 100 = 180
4 Y = 80
Y = 80/4 = 20
Then X = 40, Y = 20, and Z = 120
The first statement is true because 10 x 50 = 500
