Question

simplify 3x(4x-5)+3and find its value for 1/2=x​

Answer 1

Answer:

3x(4x - 5) + 3

⇒ 3 × 3(4 × 3 - 5) + 3 [put the value of x = 3]

⇒ 9(12-5 )+ 3

⇒ 9 × 7 + 3

⇒ 63 + 3

⇒ 66

Now,

(b) x = \bf \frac{1}{2}

2

1

⇒ 3x(4x - 5) + 3

⇒ 3 × \bf \frac{1}{2}

2

1

(4 × \bf \frac{1}{2}

2

1

- 5) + 3 [pu the value of x = \bf \frac{1}{2}

2

1

⇒ \bf \frac{3}{2}

2

3

(2 - 5) + 3

⇒ \bf \frac{3}{2}

2

3

(-3) + 3

⇒ \bf \frac{-9}{2}

2

−9

+ 3

⇒ \bf \frac{-9 + 6}{2}

2

−9+6

⇒ \bf \frac{-3}{2}

2

−3

Answer 2

Answer:

3x (4x-5)+3 = 12x²-15x +3 = 12 (1/2×1/2)-15/2+3=12×1/4-15/2+3=3 -15/2+3=6-15/2 =6×2-15÷2=12-15÷2=-3/2