Question

If -5 is the root of a quadratic equation 2x^2+px - 15=0 and the quadratic equation p(x^2+x)+k=0 has equal roots. Find k​

Answer 1

Answer:

50-5p-15=0

5p=50-15

5p=35

p=7

therefore .

p(x^2+x)+k=0

7x^2 +7x+k=0

now comparing the equations with general equations we get

a1=2,a2=7,b1=7,b2=7,c1=-15,c2=k

as roots are equal therefore(a1÷ a2)=(b1÷b2)=(c1÷c2)

therefore

2÷7=15÷k

2k=105

k=52.5