Solve x2 + 4x − 4 = 0
2 answers:
Answer:
third option
Step-by-step explanation:
Given
x² + 4x - 4 = 0 ( add 4 to both sides )
x² + 4x = 4
Using the method of completing the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(2)x + 4 = 4 + 4, that is
(x + 2)² = 8 ( take the square root of both sides )
x + 2 = ± = ± 2
( subtract 2 from both sides )
x = - 2 ± 2
You might be interested in
Answer:
<em>24 children</em>
Step-by-step explanation:
If the length of time, y hours, it takes to put a jigsaw puzzle together is inversely proportional to the number of children, x, this is represented as;
k is the constant of proportionality
If it takes 16 children 6 hours to put the jigsaw puzzle together, this means at x = 16, y = 6
Substitute:
6 = k/16
k = 6*16
k = 96
W are to find number of children needed to put the same jigsaw puzzle together in 4 hours, this is done by substituting k = 96 and y = 4 into the expression y = k/x
y = 96/4
y = 24
<em>Hence it will take 24 children to put the same jigsaw puzzle together in 4 hours</em>
<em></em>