Question

2
(a) Simplify 3x (4x - 5) + 3 and find its value
(b) Simplify a (a + a +1) + 5 and find its value for (i) a = 0, (ii) a=1
(iii) a=-1.
n​

Answer 1

Correct Question

• (a) Simplify 3x(4x-5)+3 and find its value (i) x= 3 (ii) x= 1/2
• (b) Simplify a (a + a +1) + 5 and find its value for (i) a = 0, (ii) a=1 (iii) a=-1.n

Solution

_______________________

(a) Simplify 3x(4x-5)+3 and find its value (i) x= 3 (ii) x= 1/2

$\sf~~~~\implies 3x(4x-5)+3 = (3x \times 4x) - (3x \times 5) + 3$

$\sf~~~~\implies 3x(4x-5)+3 = {12x}^{2} - 15x + 3$

For x= 3

$\sf~~~~ \: \: \: {12x}^{2} - 15x + 3 =12 \times( {3}^{2} ) - 15 \times (3)+ 3$

$\sf\quad \quad \quad \quad \quad \quad \quad \quad =12 \times( {3}^{2} ) - 15 \times (3)+ 3$

$\sf\quad \quad \quad \quad \quad \quad \quad \quad =(12 \times9) - 45+ 3$

$\sf\quad \quad \quad \quad \quad \quad \quad \quad =108 - 45+ 3$

$\sf\quad \quad \quad \quad \quad \quad \quad \quad =108 - 42$

$\sf\quad \quad \quad \quad \quad \quad \quad \quad =66$

For x= 1/2

$\sf~~~~ \: \: \: {12x}^{2} - 15x + 3 =12 \times \bigg( \dfrac{1}{2} \bigg )^{2} - 15 \times\bigg( \dfrac{1}{2} \bigg ) + 3$

$\sf\quad \quad \quad \quad \quad \quad \quad \quad= \dfrac{12}{4} - \dfrac{15}{2} + 3$

$\sf\quad \quad \quad \quad \quad \quad \quad \quad= 3 - \dfrac{15}{2} + 3$

$\sf\quad \quad \quad \quad \quad \quad \quad \quad= 6 - \dfrac{15}{2}$

$\sf\quad \quad \quad \quad \quad \quad \quad \quad= \dfrac{12 - 15}{2}$

$\sf\quad \quad \quad \quad \quad \quad \quad \quad= \dfrac{ - 3}{2}$

_______________________

_______________________

(b) Simplify a(a+a+1)+5 and find its value for (i) a = 0, (ii) a=1 (iii) a=-1.n

$\sf~~~~\implies a(a+a+1)+5 = a³ + a² + a +5$

For a = 0

Putting the value in expression

$\sf~~~~\implies a³ + a² + a +5 = {0}^{3} + {0}^{2} + 0 + 5$

$\sf\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 5$

For a= 1

Putting the value in expression

$\sf~~~~\implies a³ + a² + a +5 = {1}^{3} + {1}^{2} + 1+ 5$

$\sf\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 1 + 1 + 1 + 5$

$\sf\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 8$

For a=(-1)

$\sf~~~~\implies a³ + a² + a +5 = { - 1}^{3} + { - 1}^{2} - 1+ 5$

$\sf\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = - 1 + 1 - 1 + 5$

$\sf\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = - 2 + 6$

$\sf\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 4$

______________________

Answer 2

Answer:

hey here is your solution

so pls mark it as brainliest

Step-by-step explanation:

1.

so 3x(4x-5)+3

=12x square-15x+3

also then

a(a+a+1)+5

=a(2a+1)+5

=2a square+a+5

so first substituting value of a as 0

we would get

(2×0)+0+5

=5

now substituting value of a as 1

so we get

2×(1)square+1+5

=2+1+5

=8

now substituting value of a as -1

so we get

2×(-1) square+(-1)+5

=(2-1)+5

=1+5

=6