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4x squared + 29x + 30=0

1 Answer

5 votes

So for this equation we're going to complete the square.

Firstly, what two terms have a product of 120x^2 and a sum of 29x? 24x and 5x. Replace 29x with 24x + 5x:
4x^2+24x+5x+30=0

Next, factor 4x^2 + 24x and 5x + 30 separately. Make sure that they have the same quantity inside the parentheses:
4x(x+6)+5(x+6)=0

Now you can rewrite the equation as:
(4x+5)(x+6)=0

Now using zero product property, solve for x:


4x+5=0\\ 4x=-5\\ x=-1.25\\ \\ x+6=0\\ x=-6

In short, x = -1.25 and -6

User Terelle
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