Question

Solve the equation by completing the square. Round to the nearest tenth.

Answer 1

Answer:  The correct option is (B) 1.1, -9.1.

Step-by-step explanation:  We are given to solve the following quadratic equation by the method of completing the square.

$x^2+8x=10~~~~~~~~~~~~~~~~(i)$

In completing the square method, we need to make left hand side of the above given equation as a perfect square trinomial.

From equation (i), we have

$x^2+8x=10\\\\\Rightarrow x^2+2\times x\times 4+4^2=10+4^2\\\\\Rightarrow (x+4)^2=10+16\\\\\Rightarrow (x+4)^2=26\\\\\Rightarrow x+4=\pm\sqrt{26}\\\\\Rightarrow x=-4\pm \sqrt{26}\\\\\Rightarrow x=-4\pm 5.09\\\\\Rightarrow x=-4+5.09,~~~~~x=-4-5.09\\\\\Rightarrow x=1.09,~~~~~~~~~\Rightarrow x=-9.09.$

Rounding to the nearest tenth, we get

$x=1.1,~~-9.1.$

Thus, the required solution is x = 1.1, -9.1.

Option (B) is CORRECT.

Answer 2

B.
1.1, -9.1

$x^{2} +8x=10$