Question 879938
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Hi
f(x)= px^2 + qx + r has 
f(0)= 35, r = 35
f(x)= px^2 + qx + 35
f(1)=20 and f(2)=11
plug and play, substituting first x = 1  and then x = 2
I. 20 = p + q + 35   0r {{{-15 = p + q}}}
II. 11 = 4p + 2q + 35 0r {{{-24 = 4p + 2q}}}

 30 = -2p + -2q   |Multiplying EQ I by (-2) and ADDING Eqs I & II to eliminate q
<u> -24 = 4p + 2q</u>
    6 = 2p
    3 = p   and q  = -18  {{{-15 = 3 + q}}}
f(x)= 3x^2 -18x + 35 
f(x)= 3(x-3)^2 - 27 + 35  completing the Square
f(x)= 3(x-3)^2 +8