Question

Solve the quadratic equations

y^2 −10y+21=0
y=?

16p^2 -8p=-1
p=?

x^2 -400=0
x=?

-16m^2 =8m+1
m=?

-3n^2 +75=0
n=?

Answer 1

for quadratic equation 1

y^2-10y+21=0

Explanation:

y^2-7y-3y+21=0

y(y-7)-3(y-7)=0

(y-7)(y-3)=0

y-7=0,y-3=0

y=7,y=3

y=(3,7)

for quadratic equation 2

16p^2-8p+1=0

16p^2-4p-4p+1=0

4p(4p-1)-1(4p-1)=0

(4p-1)twice=0

4p-1=0,4p-1=0

4p=1

p=1/4 twice

for quadratic equation 3

x^2-400=0

x^2=400

x=√400

x=20

for quadratic equation 4

-16m^2-8m-1=0

multiply the equation by -

16m^2+8m+1=0

16m^2+4m+4m+1=0

4m(4m+1)1(4m+1)=0

4m+1=0 twice

m=-1/4 twice

for quadratic equation 5

-3n^2+75=0

divide both side by -3

-3n^2/-3=-75/-3

n^2=25

n=√25

n=5