Question

If a=3, b=-5 fond the value of (2a+3b) (4a sq- 6ab+9b square)​

Answer 1

Explanation:

(2a+3b)(4a²-6ab+9b²

(2a+3b){(2a)²-2a×3b+(3b)²}

Because (a³+b³)=(a+b)(a²-ab+b²)

Therefore,

(2a+3b){(2a)²-2a×3b+(3b)²}

=(2a)³+(3b)³

By substituting the values , we get

• (2a)³+(3b)³
• (2×3)³+(3×(-5))³
• 6³+(-15)³
• 216+(-3375)
• 216-3375
• -3159