With qudratic equations and complex numbers

19. 7, 14 and 24

20. 2 seconds

Step-by-step explanation:

Question 19:

We have a triangle with perimeter 45cm.

Assuming its shortest side to be x, we can write expressions for each of its sides and form an equation.

shortest side ---> x

one side is twice as long as the shortest side ---> 2x

remaining side is 25cm less than the square of the shortest side ---> x^2-25

Combing these to get:

Now factorizing this quadratic equation to get:

Therefore, the lengths of three sides of this triangle are:

x ---> 7

2x ---> 2*7 ---> 14

---> (7*7)-25 ---> 24

Question 20:

The height h (in feet) of the rock after t seconds is given by the equation:

a) initial height of the rock = 144 feet

b) Putting h = 80 to find the the seconds after the rock is dropped will it be 80 feet above the water.

The time will be 2 seconds.

2

step-by-2step explanation:

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step-by-step explanation: