SOLUTION: 19. Find the constant term that should be added to make the following expression a perfect-square trinomial. x2 + 9x (for this question my answer was 81/2 is it correct?)
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-> SOLUTION: 19. Find the constant term that should be added to make the following expression a perfect-square trinomial. x2 + 9x (for this question my answer was 81/2 is it correct?)
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Question 95830: 19. Find the constant term that should be added to make the following expression a perfect-square trinomial. x2 + 9x (for this question my answer was 81/2 is it correct?)
23. The length of a rectangle is 3 cm more than 2 times its width. If the area of the rectangle is 95 cm2, find the dimensions of the rectangle to the nearest thousandth.
24. Find the x-intercepts. y = x2 – 3x – 11
25. Find the axis of symmetry y = x2 – x
You can put this solution on YOUR website! 19. Find the constant term that should be added to make the following expression a perfect-square trinomial. x2 + 9x (for this question my answer was 81/2 is it correct?)
It has to be [(1/2)9}^2 which equals (9/2)^2
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23. The length of a rectangle is 3 cm more than 2 times its width. If the area of the rectangle is 95 cm2, find the dimensions of the rectangle to the nearest thousandth.
Let width be "x"; length = "2x+3"
Area = x (2x+3)
95 = 2x^2+3x
2x^2+3x-95 = 0
x = [-3 +- sqrt(3^2-4*2*-95)]/4
x = [-3 +- sqrt(769)]/4
x = [-3 + 27.731]/4
x = 6.1827...cm (width of the rectangle)
2x+3 = 15.3654 cm (length of the rectangle)
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24. Find the x-intercepts. y = x2 – 3x – 11
x^2-3x-11 = 0
Use the quadratic formula to find two values for "x".
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25. Find the axis of symmetry y = x^2 – x
Complete the square on the x-terms:
x^2-x + ? = y+?
x^2-x+[(1/2)(-1)]^2 = y + [1/2]^2
x^2-x+(1/4) = y+(1/4)
Factor to get:
(x-(1/2))^2 = y+(1/4)
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This tells you:
vertex at (1/2 , -1/4)
axis of symmetry: x = 1/2
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Cheers
Stan H.
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