18. 26
19. 10
20. (26×26×26)×(10×10×10) = 17576000
21. (26×26×26) × (1×10×10) = 1757600
22. (26×25×24)+(10×9×8) =11232000
23. (25×24×1)×(10×9×8) =432000
24. 3/6 × 2/13 = 1/13
Turn 7/10 into decimal. (0.7)
Keep adding by 0.7 until you get the number closest to 4.1
3.5 is the closest, if we add another 0.7, we get 4.2.
So, he can get 5 sections of 0.7m
You can multiply this out the long way using the distributive property:
.. (4x -3)*(2x^2 -7x +1)
.. = 4x*(2x^2 -7x +1) -3(2x^2 -7x +1)
.. = 8x^3 -28x^2 +4x -6x^2 +21x -3
.. = 8x^3 -34x^2 +25x -3 . . . . . . . . . . . . selection C
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Or you can recognize that the product will be a cubic with terms x^3 down to a constant.
The coefficient of x^3 can only come from 4x*2x^2 = 8x^3
The coefficient of x^2 will come from -3*2x^2 and 4x*-7x = (-6 -28)x^2 = -34x^2
This is sufficient to identify answer C as the correct choice.
If you want to continue,
The coefficient of x will come from -3*-7x and 4x*1 = (21 +4)x = 25x
The constant will come from -3*1 = -3.
All this arithmetic can be done in your head, so you can write down the answer without any intermediate "work", if you want to.
From a test-taking point of view, you can identify that the x^2 term will tell you the correct answer. You only need to calculate that one.
Answer:
The complement of a 90° angle is a 0° angle.