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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

User Udarts
by
7.3k points

1 Answer

0 votes

Answer:

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

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.

User Leogama
by
7.3k points