The graph represents the relation y = xo2 - 3x - 3. Find the value of x for which x2 - 3x = 7
Attached Figure / Diagram
A
-1.55, 4.44
B
1.55, -4.55
C
-1.55, -4.55
D
1.55, 4.55
Verified Correct Answer: A.
Step-by-Step Mathematical Solution
x2 - 3x = 7
x2 - 3x - 7 = 0
What can you add to both sides of the equation to give the same value of y = x2 - 3x - 3
The number is 4
x2 - 3x - 7 + 4 = 4
x2 - 3x - 3 = 4
but y = x2 - 3x - 3
y = 4; So are y = 4 draw a line parallel to x axis, to cut or intersect the graph. At these points look down to see the corresponding values on x axis
This give -1.55 and 4.55
Source: Myschool Past Questions Archive (Record #36674)