28a^2 – 7a^4 = 0

m^2 – 4m – 45 = 0

Please show how you got the answers. Thanks!

Summary### Quadratic equation help ?!!? in **Science **

*Quadratic equation help ?!!?* :__Quadratic equation help ?!!?__

Full Text / Question28a^2 - 7a^4 = 0 m^2 - 4m - 45 = 0 Please show how you got the answers. Thanks! …

28a^2 – 7a^4 = 0

m^2 – 4m – 45 = 0

Please show how you got the answers. Thanks!

This site uses Akismet to reduce spam. Learn how your comment data is processed.

panhead says

28a^2 – 7a^4 = 0

take common a^2 ..

a^2(28 – 7a^2)=0

a^2=0 and 28 – 7a^2=0,

a=0,0 and a^2 – 4=0(taking 7 common and reversing sign)

so,a=0,0 and (a – 2)*(a+2)=0

so,a=0,0,-2,2.

Equation 2:

m^2 – 4m – 45 = 0

m^2 – 9m+5m – 45 = 0

(m-9)(m+5)=0

so m=9 or -5.

purrpletoad says

1) 7a^2 is COMMON

7a^2 ( 4 – a^2) = 0

USE FORMULA a^2 – b^2 = ( a+b) ( a-b)

7a^2 ( 2 + a) ( 2-a) = 0

a = 0 OR -2 OR 2 ANSWER

2) m^2 -4m -45 = 0

m^2 +5m -9m -45 = 0

m ( m+5) -9( m+5) = 0

( m-9) ( m+5) = 0

m = 9 OR -5 ANSWER