FUNCTIONS K2

If f(x) = |x – 10 – x²| evaluate f(-7)

 

Solution

 

f(x) = |x - 10 – x²|

 

f(-7) = |-7 - 10 – (-7)²|

f(-7) = |-17 – (-7)²|      (since -7 - 10 = -17)

 

f(-7) = |-17 – 49|     since (-7)²= 49

 

f(-7) = |-66| = 66 since any number out of absolute signs is +ve.

  

Hence f(-7) = 66

 

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If f(x) = | x – 60 – x²| evaluate f(-8)

  

ALGEBRA C2b

 If 5x + 13y= 8 + 6x; find the x intercept.

 

Solution

 

x-intercept is when y=0.

 

5x + 13(0)= 8 + 6x.

 

5x - 6x + 13(0)= 8

 

-x + 0 = 8

 

-x = 8.

 

-x = 8    dividing by -1 both sides.

-1   -1

 

x = -8

 

Hence x-intercept is (^-8,0)

 

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If 11x - 3y= 33 + 13x; find the x intercept.