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Solve the problem. give that f(x)=4x²-7x;find all values of a such that f(a)=15 HELP!!!

1 Answer

3 votes

4x^2-7x=15\\ 4x^2-7x-15=0\\ 4x^2-12x+5x-15=0\\ 4x(x-3)+5(x-3)=0\\ (4x+5)(x-3)=0\\ x=-(5)/(4) \vee x=3
User Eriko
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