Quick Algebra 2 help PLEASE!?
Please help! I dont get this at all!
1)What is the axis of symmetry of the graph of y = 4(x - 1)2 - 3?
2)What are the x- and y-intercepts of the graph of y = 2x2 - 8x - 10
3)Solve. x2 + x = 20
Please help! I dont get this at all!
1)What is the axis of symmetry of the graph of y = 4(x - 1)2 - 3?
2)What are the x- and y-intercepts of the graph of y = 2x2 - 8x - 10
3)Solve. x2 + x = 20
Comments
1) Do you mean y = 4(x-1)^2 -3 or y = (4)(2)(x-1) -3
If you mean y = 4(x-1)^2 -3, the axis of symmetry would be x = 1. This is because from the equation, we can see that the minimum of the parabola occurs at x = 1. ( the brackets = 0, ex: 0 = x-1, x =1). Because the parabola opens along the vertical, the general shape would be "U" and the line of symmetry looks like this: \|/ (at the minimum y- value). To see a good graph, visit http://www.wolframalpha.com/input/?i=y+%3D+4%28x-1...
2) y = 2x^2 -8x -10
x-int: when y = 0
0 = 2x^2 -8x -10 <--- divide by 2
0 = x^2 -4x -5
0 = (x-5)(x+1)
x = 5, -1
y-int: when x = 0
y = 2(0)^2 -8(0) -10
y = -10
3) x^2 + x = 20
x^2 + x -20 = 0
(x-4)(x+5) = 20
x= 4, -5
3) X=4
3. X=4
you're able to start up plugging the variables into the different equations. There are 3 variables and 3 equations. one million. x - y + 3z = 23/2 x = y - 3z + 23/2 2. 3x + 2y + 2z = -6 3(y - 3z + 23/2) + 2y + 2z = -6 3y - 9z + sixty 9/2 + 2y + 2z = -6 5y - 7z = - eighty one/2 5y = -eighty one/2 + 7z y = -eighty one/10 + (7/5)z 3. 2x - z = one million/2 2(y - 3z + 23/2) - z = one million/2 2y - 6z + 23 - z = one million/2 2y - 7z + 23 = one million/2 Plug in equation from #2 2(-eighty one/10 + (7/5)z) - 7z + 23 = one million/2 -eighty one/5 + (14/5)z - 7z + 23 = one million/2 -(21/5)z + (34/5) = one million/2 (21/5)z = sixty 3/10 z = 3/2 Then plug that returned into equation 2 y = -eighty one/10 + (7/5)z y = -eighty one/10 + (7/5)*(3/2) y = -6 Then plug that returned into equation one million x = y - 3z + 23/2 x = (-26/5) - 3(3/2) + 23/2 x = one million