How do you write the quadratic function in standard form given points #(-4,-7)#, #(-3,3)#, #(3, -21)#? Algebra Quadratic Equations and Functions Quadratic Functions and Their Graphs 1 Answer mizoo Apr 28, 2018 #y = -2x^2 -4x + 9# Explanation: #y = ax^2 + bx + c# #(-4, -7):# # -7= a(-4)^2 + b(-4) + c# #16a - 4b + c = -7 => eq_1# #(-3,3):# #3 = a(-3)^2 + b(-3) + c# #9a - 3b + c = 3 => eq_2# #(3,-21):# #-21 = a(3)^2 + b(3) + c# #9a + 3b + c = -21 => eq_3# #eq_(1,2&3)# #16a - 4b + c = -7# #9a - 3b + c = 3# #9a + 3b + c = -21# #=> a = -2, b = -4, c = 9# #y = -2xxx^2 + -4xxx +9# #y = -2x^2 -4x + 9# https://www.desmos.com/calculator/njo2ytq9bp Answer link Related questions What are the important features of the graphs of quadratic functions? What do quadratic function graphs look like? How do you find the x intercepts of a quadratic function? How do you determine the vertex and direction when given a quadratic function? How do you determine the range of a quadratic function? What is the domain of quadratic functions? How do you find the maximum or minimum of quadratic functions? How do you graph #y=x^2-2x+3#? How do you know if #y=16-4x^2# opens up or down? How do you find the x-coordinate of the vertex for the graph #4x^2+16x+12=0#? See all questions in Quadratic Functions and Their Graphs Impact of this question 1396 views around the world You can reuse this answer Creative Commons License