Question

Solve the Quadratics:

1) k^2-8k=0
2) a^2+5a=0
3) 6n^2+5n-25=0
4) 2x^2-11x-21=0
5) 2n^2+13n+19=4


Bonus Word Problem:

The larger leg of a right triangle is 7cm longer than its smaller leg. The hypotenuse is 8cm longer than the small leg. How many centimeters long is the smaller leg?

Answer 1

Explanation:

1 ) k²-8k = 0

k(k-8)=0

k = 0 or k=8

2) a²+5a=0

a(a+5) = 0

a=0 or a = - 5

3 ) 6n²+5n-25=0

delta = b²-4ac b =5 and a = 6 and c= - 25

delta = 5²-4(6)(-25) = 625 = 25²

n 1 = (-5+25)/12 = 20/12 = 5/3

n 2 = (-5-25)/12 = - 30/12 = -5/2

same method for 4) and 5)