Question

Multiply: (3x + 7)(5x2 − 3x + 6) A) 15x3 + 26x2 − 39x + 42 B) 15x3 + 26x2 + 3x + 42 C) 15x3 − 44x2 − 3x + 42 D) 15x3 + 26x2 − 3x + 42

Answer 1

38.5

Explanation:

Lets say, first number = x

Second number = 3x+7

Total = 49

(x)+(3x+7)= 49

4x+7 = 49

4x = 42

x = 42/4

x= 10.5

x= 10.5

3x+7 = 3(10.5)+7 = 38.5

Hope this helps!!

Answer 2

`15x^3+26x^2-3x+42`

Explanation:

Multiply
`(3x + 7)(5x^2 - 3x + 6)`

To multiply two parenthesis , we first multiply 3x inside the second parenthesis and then we multiply 7 inside the second parenthesis

`(3x)(5x^2 - 3x + 6)=15x^3-9x^2+18x`

Now multiply 7 inside the second parenthesis

`(7)(5x^2 - 3x + 6)=35x^2-21x+42`

Now we add both the answers we got

`15x^3-9x^2+18x + 35x^2-21x+42`

Lets combine like terms

`15x^3+26x^2-3x+42`