x(x+3.7)=18.3
x^2+3.7x-18.3=0
I have tried using quadratic equation formula, tho with no luck to find the right answer. Can someone help? I need the answer to be correct to 3 sig figs

Question

x(x+3.7)=18.3
x^2+3.7x-18.3=0
I have tried using quadratic equation formula, tho with no luck to find the right answer. Can someone help? I need the answer to be correct to 3 sig figs

phi · Answer

can you show how far  you got ?

phi · Answer

Maybe this will help you https://www.khanacademy.org/math/trigonometry/polynomial_and_rational/quad_formula_tutorial/v/using-the-quadratic-formula

anonymous · Answer

$$x=\frac{ -3.7+-\sqrt{86.89} }{ 2 }=\frac{ 5.621 }{ 2 } or \frac{ -13.021 }{ 2 }$$

anonymous · Answer

then, i get either 2.811 or -6.511, so i put those into the formula:
2.811(2.811+3.7)=18.302 , and damn i just did it myself. cheers!

phi · Answer

I was going to say it looks good.

anonymous · Answer

so if I'll write 2.811 and 6.511, will it be good enough for the answer (I'm not sure about the 3sig fig part, having troubles with studying in English, lol

phi · Answer

I think 3 significant figures means just 3 digits total.  so 2.81 and -6.51

anonymous · Answer

ok, thanks. I was calculating dimensions of a rectangle, so negative is not an option. thanks!

anonymous · Answer

Refer to the Mathematica attachment.