Question

please tell me fast I will mark brainliest​

Answer 1

1) ab - bc + (bc - ca)

= ab - bc + bc - ca

= ab - ca

= a(b - c)

2) 8 - 9xy + 3x² - 5x - (3x² - 2x + 5xy - 7)

= 8 - 9xy + 3x² - 5x - 3x² + 2x - 5xy + 7

= 8 + 7 - 9xy - 5xy + 3x² - 3x² - 5x + 2x

= 15 - 14xy - 3x

3) (x + 7) (x + 7)

= (x + 7)²

(a + b)² = a² + b² + 2ab

(x + 7)² = x² + 7² + 2×x×7

= x² + 49 + 14x

4) (3x +1) (3x - 8)

= 3x× 3x - 3x × 8 + 3x - 8

= 9x² - 24x + 3x - 8

= 9x² - 21x - 8

Answer 2

Answer:

Step-by-step explanation:

(ab-bc) + (bc-ca)

ab-bc+bc-ca= ab-ca

(3x²-2x+5xy-7) -(8-9xy+3x²-5x)

3x²-2x+5xy-7-8+9xy-3x²+5x

Collect the like terms

3x²-3x²+5xy+9xy+5x-2x-7-8

=14xy+3x-15

(x+7)(x+7)

x(x+7)+7(x+7)

=x²+7x+7x+49=x²+14x+49

(3x+1)(3x-8)

3x(3x-8)+1(3x-8)

9x²-24x+3x-8

=9x²-21x-8