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What is the x-coordinate at the point of intersection of y1= 2(5x + 3) and y2= x2 − 15? Consider only the positive value of x, and round the value to nearest hundredth.

Respuesta :

so when does y1 = y2?

at
2 (5x + 3) = (x2 -15)

solve and advise answer in comments and will assist further

Solution

The equation of two curves are

     [tex]y_{1}=y=2 \times (5 x+3)\\\\y_{2}=y=x^2-15[/tex]

Equating the two curves that is y values, to find their point of Intersection

→  2 × (5 x+3)=x²-15

→10 x +6=x²-15⇒⇒Used distributive property of multiplication with respect to addition

→x² -10 x -15 -6=0

→x² -10 x-21=0

For a Quadratic equation of the type

   [tex]\rightarrow ax^2+b x +c=0\\\\x=\frac{-b \pm \sqrt{D}}{2 a}\\\\D=b^2-4ac[/tex]  

Using discriminant method to solve the problem

   [tex]x=\frac{-(-10)\pm\sqrt{(-10)^2-4 \times 1 \times (-21)}}{2 \times 1}\\\\x=\frac{10 \pm \sqrt{100+84}}{2}\\\\x=\frac{10 \pm \sqrt{184}}{2}\\\\x=5 \pm \sqrt{46}\\\\x_{1}=5+6.78\\\\x_{1}=11.78\\\\x_{2}=5-6.78\\\\x_{2}=-1.78[/tex]

The x coordinate of point of intersection are, 11.78 and -1.78.