ALGEBRA 1 Exam9 Describe and correct the error 7 3x22x3 3x2x

ALGEBRA 1 Exam9 Describe and correct the error. 7. (3x-2(2x-3) 3x(2x-3)-2(2x-3) 6x-13x-6 Completely factor the following expressions. 9 2+11-42 11. 144-9p 12. Sc -24cd-5d 13·w\"-15w, + 54 56

Solution

7) (3x -2)(2x -3)

= 3x(2x -3) -2(2x -3)

= 6x^2 - 9x -4x + 6

The error is multiplication -2 x -3 = +6

8) t^2 +4tv + 4v^2

It matches the expansion of (a+b)^2 = a^2 +b^2 +2ab

So.t^2 +4tv + 4v^2 = (t +2v)^2

9) z^2 +11z -42

factorise : z^2 +14z -3z -42

= z( z +14) -3(z +14)

= (z -3)(z +14)

10) 4x^2 - 8x -12 +6x

group together: ( 4x^2 -8x ) + (-12 +6x)

4x(x -2) + 6(x -2)

(4x+6)(x -2)