Leaving Cert Factors FACTORS Difference of 2 squares

Leaving Cert Factors

FACTORS

Difference of 2 squares

Factorise the following 6 x + 24 y 5 ab+ 15 bc 7 x² - 28 x 6( x + 4 y) 5 b( a + 3 c) 7 x( x – 4) 4 x² -6 xy +8 xz 5 xy² - 20 x²y 2 a²b -4 ab² +12 abc 2 x( 2 x -3 y + 4 z) 5 xy( y – 4 x) 2 ab( a – 2 b+ 6 c)

Factorising x² + 4 x x ( x + 4 ) X² - 36 (x – 6) (x + 6) 2 x² + 4 x 2 x (x + 2) 4 x² - 100 (2 x + 10) ( 2 x – 10)

Method 1 Brackets Method 2 Big X Method 3 Guide Number

Factorising when there is a number in front of the x² 3 x² + 13 x + 4 (3 x + 1) (x + 4) check (3 x)(4) + (1)(x) = 12 x + 1 x = 13 x 8 x² +10 x - 3 (8 x + 1) (x - 3) check (8 x)(-3)+ (1)(x) = -24 x + 1 x = -23 x . . . . wrong, try again (4 x ‑ 1) (2 x + 3) check (4 x )(3) + (‑ 1)(2 x) = 12 x ‑ 2 x = 10 x. . . . correct

Method 1 Brackets Method 2 Big X Method 3 Guide Number

Simplify each of the following, using factors where necessary 8 x + 8 y x² + 8 x+7 a² - 16 8 x+1 3 a - 12 8( x + y) 8 =x+y (x + 7) ( x + 1) x+1 =x+7 (a + 4) (a – 4 ) 3( a – 4) 3 a+4

Factorising, using the quadratic formula x 2 – 4 x – 3 = 0 a = 1 b = - 4 c = - 3 X = 9. 291 2 or x = - 1. 291 2 X = 4. 645 or x = - 0. 645 X = 4. 6 or x = - 0. 6

Method 1 Using Factors Method 2 Using Quadratic Formula

Method 1 Using Factors Method 2 Using Quadratic Formula