## anonymous one year ago Help please Find the equation of the axis of symmetry and the coordinates of the vertex of the graph of the function y = –2x^2 +6x – 1. A) x = 3; vertex: (3, 35) B) x = –1.5; vertex: (–1.5, – 14.5) C) x = –1.5; vertex: (–1.5, –5.5) D) x = 1.5; vertex: (1.5, 3.5)

1. popitree

from the equation, after simplifying u will get $(x-\frac{ 3 }{ 2 })^{2} = -\frac{ y }{ 2 }+\frac{ 7 }{ 4 }$

2. popitree

now can u solve

3. Nnesha

this question is same just like we did on the previous thred $\huge\rm \frac{ -b }{ 2a }$ use this formula to find x-coordinate of the vertex

4. anonymous

IN the general quadratic$y=ax^2 + bx + c$the axis of symmetry is the vertical lineline$x=-\frac{ b }{ 2a }$Yhis also gives the x-coordinate of the vertex. Plug this value of x back into the function to get the y-coordinate of the vertex.

5. Nnesha

and then replace x by its value into the equation to find y-coordinate axis of symmetry = x coordinate of the vertex

6. anonymous

can we go over this step by step.. still confused So I replace b with -2 and a with 6? @Nnesha

7. Nnesha

no $\huge\rm Ax^2+Bx+C=0$ B is middle term A is leading coefficient

8. anonymous

Oh actually the opposite I mean.. -2 -> a and 6 -> b

9. Nnesha

yes!!

10. Nnesha

substitute b and a by their values into the formula

11. anonymous

-(6)/2(-2)

12. Nnesha

yes!

13. anonymous

so now we divide by -2?

14. Nnesha

there is 2(-2) you can multiply them first or reduce the fraction

15. anonymous

-(6)/-4

16. Nnesha

yes right :=)

17. Nnesha

can you reduce the fraction -6/-4 = ?

18. anonymous

so now we simplify

19. anonymous

yes divide by 2 or -2

20. Nnesha

okay so -6/-4 = ?

21. anonymous

3/2

22. anonymous

and then 3/2 = 1.5 right?

23. Nnesha

yes right

24. Nnesha

now find y-coordinate of the vertex

25. anonymous

y = -2(1.5)^2 + 6(1.5) - 1?

26. Nnesha

yes

27. anonymous

= 3.5

28. anonymous

29. anonymous

D) x = 1.5; vertex: (1.5, 3.5)

30. Nnesha

yes right!

31. anonymous

thanks

32. Nnesha

my pleasure