Question

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

x^2 + 8x = 10

A. 1.1, 9.1
B. 1.1, -9.1
c. -1.1, 9.1
D. -1.1, -9.1

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* x* 4+4^2=10+4^2\\\\\Rightarrow (x+4)^2=10+16\\\\\Rightarrow (x+4)^2=26\\\\\Rightarrow x+4=\pm√(26)\\\\\Rightarrow x=-4\pm √(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`