Two linear factors of x2-15x+56
are
a) (x-7)(x+8)
b) (x+7)(x-8)
c) (x-7)(x-8)
d) (x+7)(x+8)
Solution:x2-15x+56=0
x2-8x-7x+56=0
x(x – 8) – 7(x – 8)= 0 (x – 8)(x – 7)=0
x – 8=0 , x – 7=0
x=8 , x=7
A root of an equation ,
which does not satisfy the equation is called………
a) Pure root
b) quadratic root
c) Determinant
d)Extraneous root
The solution set of equation 5x2=30x is:
a) {5,30}
b) {0,6)
c) {0,-6}
d) {5,0}
Solution:5x2= 30 x 5x2– 30x=0
5x(x – 6)= 0 5x= 0 , x – 6=0
x=0 , x=6
The solution set of equation x2-x-2=0 is :
a) {2,1}
b) {-2,1}
c) {2,-1}
d) {-2,-1}
Solution:x2– x – 2=0 x2– 2x+x – 2=0
x(x – 2)+1(x – 2)= 0 (x – 2)(x+1)=0
x – 2=0 , x+1= 0
x=2 , x=-1
