Page 303 - MATHEMATICS COURSE FOR SECONDARY SCHOOLS BOOK 2

The equation of the y – axis x = 0.
Graphical method
Graphical method
A graphical method can also be used to solve this
Example 4
problem.
A graphical method can also be used to solve this problem.
First draw the graph of y = 4x2 - 28 x + 49 for a domain, say, 0 ≤ x ≤ 49. 􏰁
Firstdrawthegraphofy=4􏰀 -28x+49foradomain,say,0􏰄x􏰄49. x01234567
􏰀􏰁 0 4􏰀􏰁 0 -28 x -0 49 49 y 49
1 4
4 16 -28 -56 49 49 25 9
9 16 25 36 64 100 -84 -112 -140 49 49 49
1 1 9
36 49 144 196 -168 -196 49 49 25 49
ThTehsetsoeftorfdoerrdeedrepdaiprsair{s(0{,(409,)4,9()1,2(15,)2,5(2),,9()2(,39,)(3,1),(4,1)(5,9)(6,25)(7,49)}
1), (4, 1) (5, 9) (6, 25) (7, 49)}, is then used to plot
poIisnttshoen ausCeadrteosipalnotpplaonine;tsgroanpha pCaapreterswiainthpalaxnese; graph paper with axes and scales. A
smooth curve is then drawn connecting the points that were plotted using the set of
and scales. A smooth curve is then drawn con-
y
x=0 50
40
30 20 10
ordered pairs.
necting the points that were plotted using the set of ordered pairs.
y=4x2-28 +49
x=2 12 y=0 01234567
x
297