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what are the solutions to the system of equations [tex]y = (x + 4){2} - 1[/tex]and [tex]y = - 3 - 13[/tex]

What Are The Solutions To The System Of Equations Texy X 42 1texand Texy 3 13tex class=

Sagot :

We are given the following two equations

[tex]\begin{gathered} y=(x+4)^2-1\qquad eq.1_{} \\ y=-3x-13\qquad eq.2 \end{gathered}[/tex]

Since both equations are equal to y then we can equate them as

[tex](x+4)^2-1=-3x-13[/tex]

Now let us simplify the equation

[tex]\begin{gathered} (x+4)^2-1=-3x-13 \\ x^2+2(x)(4)+4^2-1=-3x-13 \\ x^2+8x+16-1=-3x-13 \\ x^2+8x+3x+16-1+13=0 \\ x^2+11x+28=0 \end{gathered}[/tex]

As you can see, we are left with a quadratic equation.

The standard form of a quadratic equation is given by

[tex]ax^2+bx+c=0[/tex]

Comparing the equation with the standard form, the coefficients are

a = 1

b = 11

c = 28

Now recall that the quadratic formula is given by

[tex]x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}[/tex]

Substitute the values into the above quadratic formula

[tex]x=\frac{-11\pm\sqrt[]{(11)^2-4(1)(28)}}{2(1)}=\frac{-11\pm\sqrt[]{121^{}-112}}{2}=\frac{-11\pm\sqrt[]{9}}{2}=\frac{-11\pm3}{2}[/tex]

So the two possible solutions are

[tex]\begin{gathered} x_1=\frac{-11+3}{2},\: x_2=\frac{-11-3}{2} \\ x_1=\frac{-8}{2},\: x_2=\frac{-14}{2} \\ x_1=-4,\: x_2=-7 \end{gathered}[/tex]

Therefore, the solutions of the equations are

x = -4 and x = -7