Question

Factor completely. 100-140x+49x^2

Answer 1

(10 - 7x)²

Explanation:

Answer 2

(10 - 7x)²

Explanation:

Note that this expression is a perfect square of the form

(a - bx)² = a² - 2abx + b²x²

Compare 100 - 140x + 49x² to the above

a² = 100 ⇒ a =
`√(100)` = 10

b² = 49 ⇒ b =
`√(49)` = 7

and - 2ab = - 2 × 10 × 7 = - 140, thus

100 - 140x + 49x² = (10 - 7x)² ← in factored form