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Leaving Cert Factors. FACTORS. Difference of 2 squares. Factorise the following 6x + 24y 5ab + 15bc 7x² - 28x 6( x + 4y) 5b( a + 3c) 7x( x – 4)
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Factorise the following • 6x + 24y 5ab+ 15bc 7x² - 28x • 6( x + 4y) 5b( a + 3c) 7x( x – 4) • 4x² -6xy +8xz 5xy² - 20x²y 2a²b -4ab² +12abc • 2x( 2x -3y + 4z) 5xy( y – 4x) 2ab( a – 2b+ 6c)
Factorising x² + 4x 2x² + 4x x ( x + 4 ) 2x (x + 2) X² - 36 4x² - 100 (x – 6) (x + 6) (2x + 10) ( 2x – 10)
Method 1 Brackets Method 2 Big X Method 3 Guide Number
x² + 6x + 8x² +3x ‑ 10 x² -2x ‑ 24 (x + 2) (x + 4) (x ‑ 2) (x + 5) (x – 6) (x + 4)
Factorising when there is a number in front of the x² 3x² + 13x + 4 (3x + 1) (x + 4) check (3x)(4) + (1)(x) = 12x + 1x = 13x 8x² +10x - 3 (8x + 1) (x - 3) check (8x)(-3)+ (1)(x) = -24x + 1x = -23x ....... wrong, try again (4x ‑ 1) (2x + 3) check (4x )(3) + (‑1)(2x) = 12x ‑ 2x = 10x ....... correct
Method 1 Brackets Method 2 Big X Method 3 Guide Number
Simplify each of the following, using factors where necessary • 8x + 8yx² + 8x+7 a² - 16 • 8 x + 1 3a - 12 8( x + y) (x + 7) ( x + 1) (a + 4) (a – 4 ) 8 x + 1 3( a – 4) = x + y = x + 7 a + 4 3
Factorising, using the quadratic formula x2 – 4x – 3 = 0 a = 1 b = - 4 c = - 3 X = 9.291 or x = - 1.291 2 2 X = 4.645 or x = - 0.645 X = 4.6 or x = - 0.6
Method 2 Using Quadratic Formula Method 1 Using Factors
Method 1 Using Factors Method 2 Using Quadratic Formula