A-level maths question?
a) solve the equation 4x^2+12x-0
f(x)=4x^2+12x+c
where c is a constant
b)given that f(x)=0, has equal roots, find the value of c and hence solve f(x)=0
anyone who can solve this is smart if u ask me lol :)
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Verified answer
f'(x) = 8x + 12
equal roots, so f'(x) = 0
8x + 12 = 0
x = -3/2
f(-3/2) should get u 0
4(-3/2)^2 + 12(-3/2) + c = 0
9 - 18 + c = 0
c = -9