(−6)∙(a+2b−3c−4d)−(−2)∙(−4a−3b+2c+d)
2 answers:
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Answer:
∠ C = 58°
Step-by-step explanation:
DB is a perpendicular bisector , so
∠ ADC = 2 × 32° = 64°
Since AD = CD then Δ ACD is isosceles with the base angle congruent , then
∠ C = =
= 58°
The correct answer is d.
We have the following system of linear equations:
(I)
(II)
Let's use the elimination method, then let's multiply the equation (1)
and subtracting (I) and (II):
(I)
∴
(I)
(II)
____________________
(III)
∴
We can find the value of x by substituting y either in (I) or (II). Thus, from (I):
∴
∴
∴
∴
Let's substitute the values of x and y into (I) and (2)
(I)
(II)
Finally the answer is:
We have the following system of linear equations:
(I)
(II)
Let's use the elimination method, then let's multiply the equation (1)
(I)
∴
(I)
(II)
____________________
(III)
∴
We can find the value of x by substituting y either in (I) or (II). Thus, from (I):
∴
∴
∴
∴
Let's substitute the values of x and y into (I) and (2)
(I)
(II)
Finally the answer is: