Question

2.5.15
When given the equation - 23 = x² + 8x, a student says that you can add 64 to each side of the equation to complete the square. Is the student correct? If not,
describe and correct the error
r
u l in the anwar hoy to complete your choice

Answer 1

Answer:

A student is incorrect, he should add 16, not 64.

Step-by-step explanation:

Given the equation $- 23 = x^2 + 8x$

To use formula

$(a+b)^2=a^2+2ab+b^2,$

note that

$8x=2\cdot x\cdot 4,$

so we need to add $4^2=16$ to complete the square

Therefore,

$-23+16=x^2+8x+16\\ \\-7=(x+4)^2$

A student is incorrect, he should add 16, not 64.