ANSWERS FROM 800 SCORER
1.FLinearFEquation
IfF3x+7=25,FwhatFisFtheFvalueFofFx?
A.F4
B.F5
C.F6
D.F8
F CorrectFAnswer:FC.F6
Solution:
3x+7=25
SubtractF7:
3x=18
,DivideFbyF3:
x=6
Rationale:
SolveFoneFstepFatFaFtimeFbyFisolatingFtheFvariable.
2.FSystemsFofFEquations
If:
x+y=10
x−y=4
WhatFisFtheFvalueFofFx?
A.F3
B.F5
C.F7
D.F10
FCorrectFAnswer:FC.F7
Solution:
AddFbothFequations:
,(x+y)+(x−y)=10+4
2x=14
x=7
Rationale:
AddingFequationsFeliminatesFy,FallowingFyouFtoFsolveFforFx.
3.FQuadraticFEquation
WhatFareFtheFsolutionsFof:
x
2
−9=0
A.Fx=3Fonly
B.Fx=−3Fonly
C.Fx=3ForFx=−3
D.Fx=9
F CorrectFAnswer:FC
Solution:
x
2
, =9
TakingFsquareFroots:
x=±3
Rationale:
AFsquaredFnumberFcanFhaveFbothFpositiveFandFnegativeFroots.
4.FPercentageFProblem
AFjacketFcostsF$80FandFisFdiscountedFbyF25%.FWhatFisFtheFsaleFprice?
A.F$20
B.F$55
C.F$60
D.F$75
CorrectFAnswer:FC.F$60
F
Solution:
Discount:
25%×80=0.25(80)=20