Ex1:
X^4-13x^2+36=0
(x^2)^2-=363x^2+36=0 => u=x^2
u^2-13u+36=0
(u-9)(u-4)
UX^2=9 or x^2=4
x=+/-3 or x=+/-2
x= 3,-3,2,-2
Ex2:
2(4m-3)^2+7(4m-3)+5=0
4m-3=p=>2p^2+7p+5=0
(2p+5)(p+1)=0
p=-5/2 or p=-1
4m-3=5/2 or 4m-3=-1
4m= -5/2+3
4m=1/2
m=1/8
m=1/2
m= 1/8,1/2
m=1/8
When solving these problems remember that after you have solved for U you must remember to substitute and solve for the values of the original variable.
ReplyDelete