2r+1+(−4r)+7
how do i solve this equation

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?

Kathy spent 5/8 of her money on books and another 1/6 of her money on stationeries.what fraction of kathy’s money was left?

Triangle knm is what is true about the sides of knm