I need help with this

a)7x - 10

b) 70 g

Step-by-step explanation:

a)

Mass of 1st chemical which was mixed = 10g

Mass of 2nd chemical which was mixed = 2x

Mass of 3rd chemical which was mixed = 5x-20

So total mass of the the mixture which was formed after mixing all the 3 chemicals are =

10 + 2x + 5x - 20

=> 7x - 10

b)

Mass of the mixture = 235 g

From (a) , we know that

7x - 10 = 235

=> 7x = 235 + 10 = 245

=> x = 245 / 7 = 35

Hence x = 35

We also know that mass of the 2nd chemical was = 2x.

So putting the value of x gives :-

2 × 35 = 70 g