Question

Q.21 Factorise:

(i) 2 12 7 1 x x − + (ii) 2 84 2 2 − −r r (iii) 2 7 2 10 4 2
please answer fast it is for my exam practice its urgent​

Answer 1

1) 12x²+7x+1

12x²+4x+3x+1

(splitting the middle term)

4x(3x+1)+1(3x+1)

(3x+1)(4x+1)

2) Given quadratic expression in variableris

84-2r-2r²

=2(42-r-r²)/* Taking 2common */

= 2( 42 -7r+6r-r²) /* splitting the middle term */

= 2[7(6-r)+r(6-r)]

=2(6-r)(7+r)

Therefore,.

2,(6-r)and(7+r)are factors of given quadratic expression.

••••

3)√2x^2+7x+5√2=0

(√2x^2+5x)+(2x+5√2)=0

√2x(√2x+5)+√2(√2x+5)=0

(√2x+5)(√2x+√2)=0

√2x+5=0 √2x+√2=0

√2x=-5 √2x=-√2

x=-5/√2 x=-√2/√2

x=-1

Hope these helps you....