Hello, I'm from Indonesia. I hope that answer your question.
23. not equivalent because the first row 3x-9y=5 then if you multiplied this equation by 2 it will be 2(3x-9y) = 2(5) so 6x-18y= 10 not 6x-9y=10
24.equivalent because the second row 2y-6x=8 multiplied by 2 is 2(2y-6x)= 2(8) so 4y-12x=16
25. equivalent because the first row 5x+3y=19 multiplied by 2 is 2(5x+3y) = 2(19) SO 10X+6Y=38 and the second row 2x+4y=20 multiplied by 5 is 5(2x+4y)= 5(20) so 10x+20y=100
Recall that i represents the square root of -1, so by squaring it we get -1.
(2 + 4i)(7 - 3i)
= 14 - 6i + 28i + 12
= 26 + 22i
11/36 would be the probability of getting 4 , when two dice are thrown simultaneously.
As there are 6 faces of die,
So Probability of Not getting four in one dice = 
As both events are mutually exclusive, the probability of not getting four in two dice = 
So probability of getting at least one four is = 
So probability = 
Learn more about probability refer:
brainly.com/question/24756209
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