Question 576132
This is actually 3 points,
( 1/2,0), (6,0), and(2,-56)
I can write:
(1) {{{ 0 = a*(1/2)^2 + b*(1/2) + c }}}
(2) {{{ 0 = a*6^2 + b*6 + c }}}
(3) {{{ -56 = a*2^2 + b*2 + c }}}
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(1) {{{ (1/4)*a + (1/2)*b + c = 0 }}}
(1) {{{ a + 2b + 4c = 0 }}}
(2) {{{ 36a + 6b + c = 0 }}}
(3) {{{  4a + 2b + c - 56 }}}
Subtract (1) from (3)
This is 3 equations and 3 unknowns, so
you can solve for a,b, and c to get
{{{ f(x) = ax^2 + bx + c }}}