DONT SKIP please I need help with 6,7,8

How many grams must be adde to 970g to make 1 and a half kg

Achemist has 200 ml of a 10% sucrose solution. she adds x ml of a 40% sucrose solution. the percent concentration, y, of the final mixture is given by the rational function: the chemist needs the concentration of the final mixture to be 30%. how many milliliters of the 40% solution should she add to the 10% solution to get this concentration?

The lines shown below are parallel. if the green line has a slope of -1, what is the slope of the red line?