(8+i)+(-3-4i)?
A.3i
B.5-3i
C.5+3i
D.5
Question 2
(3+2i)-(-5+6i)
A.6
B.6i
C.8+4i
D.8-4i
Question 3
The system has 2 solutions.
2x-y+1=0
y=x2 - 9
True
False
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2016-11-21 3:13 pm
回答 (3)
2016-11-21 7:56 pm
1
8 + i - 3 - 4I = 5 - 3i ----------B
2
8 - 4 i---------D
3
True
8 + i - 3 - 4I = 5 - 3i ----------B
2
8 - 4 i---------D
3
True
2016-11-21 3:52 pm
Q1 : B, Q2 : D, Q3 2x-y+1 = 0, ie., y+9 =2(x+5)..[1]. y+9 = x^2..[2]. Then x^2 = 2(x+5), ie.,
x^2 -2x = 10, ie., x^2 -2x +1 = (x-1)^2 = 10+1 = 11 = (rt1)^2 & x = 1(+/-)rt11 = -10 or 12. Corresponding y = (2x+1) = -19 & 25. System has 2 solutions (x,y) = (-10,-19) & (12,25). Therefore
true.
x^2 -2x = 10, ie., x^2 -2x +1 = (x-1)^2 = 10+1 = 11 = (rt1)^2 & x = 1(+/-)rt11 = -10 or 12. Corresponding y = (2x+1) = -19 & 25. System has 2 solutions (x,y) = (-10,-19) & (12,25). Therefore
true.
2016-11-21 4:50 pm
Question 1
(8 + i) + (-3 - 4i)
= 5 - 3i
B.5 - 3i
Question 2
(3 + 2i) -(-5 + 6i)
= 8 - 4i
D. 8 - 4i
Question 3
The system has 2 solutions.
2x - y + 1 = 0
y = x^2 - 9
x = 1 + sqrt(11), y = 3 + 2 sqrt(11)
True
(8 + i) + (-3 - 4i)
= 5 - 3i
B.5 - 3i
Question 2
(3 + 2i) -(-5 + 6i)
= 8 - 4i
D. 8 - 4i
Question 3
The system has 2 solutions.
2x - y + 1 = 0
y = x^2 - 9
x = 1 + sqrt(11), y = 3 + 2 sqrt(11)
True
收錄日期: 2021-04-23 23:48:37
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