Answer:
x ≈ 1.32, x ≈ - 5.32
Step-by-step explanation:
Given
x² + 4x - 7 = 0 ( add 7 to both sides )
x² + 4x = 7
To complete the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(2)x + 4 = 7 + 4
(x + 2)² = 11 ( take the square root of both sides )
x + 2 = ± 
( subtract 2 from both sides )
x = - 2 ± 
Thus
x = - 2 - ≈ - 5.32 ( to 2 dec. places )
x = - 2 + ≈ 1.32 ( to 2 dec. places )
Step-by-step explanation:
= 3 - 5
= -2
line in the picture
Answer: $70 per year.
Step-by-step explanation:
Let's say that x is the number of years that has passed and y is how much the stamp is worth.
So we know that in zero years the stamp was worth $420 because that is the time Sheri gave her brother Sam the stamp. That could bring up the coordinates (0,420) .
Now we know that in 8 years it was worth $980 and that could be the coordinates (8,980)
To find the rate of change we need to find the different between the y value and divide it by the difference in the x values.
420 - 980 = -560
0-8 = -8
-560/-8 = 70
The rate of change is 70 which means that it grew by $70 every year.
Answer:
a) (-9,3)
Step-by-step explanation:
x + 2y = -3
- (x - y = -12)
<u />
x + 2y = -3
<u>- x + y = 12</u>
3y = 9
y = 3
x - y = -12
x- 3 = -12
x= - 9
(-9, 3)
