Question

Penelope determined the solutions of the quadratic function by completing the square. F(x) = 4x2 8x 1 –1 = 4x2 8x –1 = 4(x2 2x) –1 1 = 4(x2 2x 1) 0 = 4(x 2)2 0 = (x 2)2 0 = x 2 –2 = x What error did Penelope make in her work? Penelope should have subtracted 1 from both sides instead of adding 1. Penelope should have subtracted 4 from both sides instead of adding 1. Penelope should have added 4 to both sides instead of adding 1. Penelope should have subtracted 8 from both sides instead of adding 1.

Answer 1

By solving the quadratic equation using completing the square method we got that Penelope should have added 4 to both sides instead of adding 1.

What is quadratic equation ?

Any equation of the form $ax^2+bx+c=0$ where x is variable and a, b, and c are any real numbers where a ≠ 0 is called quadratic equation .

Given work of Penelope is

$\begin{aligned}&f(x)=4 x^{2}+8 x+1 \\&-1=4 x^{2}+8 x \\&-1=4\left(x^{2}+2 x\right) \\&-1+1=4\left(x^{2}+2 x+1\right) \\&0=4(x+2)^{2} \\&0=(x+2)^{2} \\&0=x+2 \\&-2=x\end{aligned}$

Now we can see that Penelope determined the solutions of the quadratic function by completing the square. so he must have been done as following

$\begin{aligned}&f(x)=4 x^{2}+8 x+1 \\&-1=4 x^{2}+8 x \\&-1=4\left(x^{2}+2 x\right) \\&-1+4=4\left(x^{2}+2 x+1\right) \\&3=4(x+2)^{2} \\&\frac{3}{4} =x+2)^{2} \\&\frac{\pm\sqrt3}{2} =x+2 \\&\frac{-2\pm\sqrt3}{2} =x\end{aligned}$

By solving the quadratic equation using completing the square method we got that Penelope should have added 4 to both sides instead of adding 1.

To learn more about quadratic equations visit : brainly.com/question/1214333