Logan genetically engineered a new type of fir tree and a new type of pine tree. the combined height of one fir tree and one pine tree is 21 meters. the height of 4 fir trees stacked on top of each other is 24 meters taller than one pine tree. how tall are the types of trees that logan genetically engineered?

You would need 2 unknowns for this problem since there are 2 types of trees.   Let f = height of fir a tree and p = height of a pine tree. Now translate the words.   The combined height of one fir and one pine tree is 21 meters.  The equation would be f + p = 21 Four fir trees would be 24 meters taller than one pine tree.  The equation would be 4f = 24 + p You have a system of equations.  One way to solve this system would be to solve the first equation for p.  This would  give you p = 21 - f. Take the 21 - f and substitute it into the 2nd equation for p. This will give you 4f = 24 + 21 - f. Solving this equation, you would add f to both sides and combine 24 +21 giving you 5f = 45. Divide both sides by 5 and you get f = 9 meters.  Thus the height of the fir tree is 9 meters.   To find the height of the pine tree put the 9 meters back into the first equation (f + p =21) and you have 9 + p = 21.  When you solve this equation you would find that p = 12 meters. CHECK:  Put the 9 meters for the fir tree and 12 meters for the pine back into BOTH equations and see if BOTH are  correct. f + p = 21     9 + 12 = 21   is correct 4f = 24 + p  4(9) = 24 + 12                    36 =   36   is also correct The check works.  So a fir tree is 9 meters tall and a pine tree is 12 meters tall. I don't know what the question was, but this might help.