Question

Can u help plzzzz!!

Answer 1

Lets get started :)

a) m(x) = (x - 5)(3 + 2x) - x² + 25
                   ↓         
       Open Brackets
                   ↓
       = (x × 3) + (x × 2x) + (-5 × 3) + (-5 × 2x) - x² + 25
       = 3x + 2x² - 15 - 10x - x² + 25    (Bring like-terms together in descending power order)
       = 2x² - x² + 3x - 10x - 15 + 25
       = x² - 7x + 10

b) In x² - 7x + 10, -7 is the sum and + 10 is the product
                  - 2 + - 5 = -7
                  - 2 × -5 = 10

So the factor of x² - 7x +10 is:
                   ↓
           (x - 2)(x - 5)
Solving ( x - 2 )( x - 5 ) = 0
                 ↓          ↓
           x - 2 =  0 | x - 5 = 0
             x = 2     |    x = 5