Question

(4x-5)(4x+1) (using identities)

Answer 1

Answer:

.

Step-by-step explanation:

(a-b)(a+b)=a square-2ab+b square

Answer 2

$\huge{ \underline{ \overline{ \mid{ \mathfrak{ \purple{ \: \: SOLUTION \: \: } \mid}}}}}$

$\huge{ \underline{ \mathsf{ \red{ \: \: Using \: \: identity \: \: }}}}</p><p>$

$\underline{ \underline{ \mathbb{ \pink{ \: \: \star : IDENTITY \: \: \: USED \: : \mapsto \: }}}} \\ \\ \boxed{ \green{\mathtt{ \: (x + a)(x + b) = x {}^{2} + (a + b)x + ab \: }}}$

$\: \: \: \: \: \: \: \: \: \mathtt{(4x - 5)(4x + 1)} \\ \\ \mathtt{ = (4x) {}^{2} + \{ ( - 5) + 1 \} \times( 4x )+ \{( - 5) \times 1 \}} \\ \\ \mathtt{ = 16x {}^{2} + ( - 5 + 1) \times 4x + ( - 5) } \\ \\ \mathtt{ = 16x {}^{2} + ( - 4) \times 4x - 5} \\ \\ \mathtt{ = 16x {}^{2} - 16x - 5}$

$\huge{ \underline{ \mathsf{ \red{ \: \: Without \: \: using \: \: identity \: \: }}}}$

$\: \: \: \: \: \: \mathtt{(4x - 5)(4x + 1)} \\ \\ \mathtt{ = 4x(4x + 1) - 5(4x + 1)} \\ \\ \mathtt{ =( 4x \times 4x + 4x \times 1) - (5 \times 4x + 5 \times 1)} \\ \\ \mathtt{ = 16x {}^{2} + 4x - 20x - 5 } \\ \\ \mathtt{ = 16x {}^{2} - 16x - 5}$