Looking for reliable answers? Westonci.ca is the ultimate Q&A platform where experts share their knowledge on various topics. Join our platform to connect with experts ready to provide accurate answers to your questions in various fields. Join our platform to connect with experts ready to provide precise answers to your questions in different areas.

2x^2 -16x+30=0
solve the equation


Sagot :

Divide by 2. You will have:
[tex]x^2-8x+15=0[/tex]

First method:

[tex]x^2-8x+15=0 \\ x^2-8x=-15 \qquad \qquad /+16 \\ \underbrace{x^2-8x+16}_{(x-4)^2}=-15+16 \\ \\ (x-4)^2=1 \qquad /\sqrt{} \\ |x-4|=1 \\ \hbox{From deefinition of value absolute:} \\ x_1-4=1 \qquad \hbox{and} \qquad x_2-4=-1 \\ \hbox{So solutions are:} \\ x_1=5 \\ x_2=3[/tex]

Second method:

[tex]x^2-8x+15=0 \\ \Delta= (-8)^2 -4 \cdot 15 \cdot 1 = 64-60=4 \\ \sqrt{\Delta}=2 \\ \hbox{So solutions are:} \\ x_1=\frac{8+2}{2}=5 \\ x_2=\frac{8-2}{2}=3[/tex]

Thirt method:

[tex]x^2-8x+15=0 \\ \hbox{See, that} \ \ -8x= -5x - 3x : \\ \underbrace{x^2-5x}_{x(x-5)} \underbrace{-3x+15}_{-3(x-5)}=0 \\ \\ x(x-5)-3(x-5)=0 \\ \hbox{Factor out the} \ \ x-5: \\ (x-3)(x-5)=0 \\ \hbox{Each factor have to be zero, so:} \\ x-3=0 \\ x-5=0 \\ \hbox{So:} \\ x_1=3 \\ x_2 = 5[/tex]

CHOOSE YOUR FAVOURITE METHOD! :)