Part d
in some cases, neither of the two equations in the system will contain a variable with a coefficient of 1, so we must take a further step to isolate it. let's say we now have
3c+4d=5
2c+5d=2
none of these terms has a coefficient of 1. instead, we'll pick the variable with the smallest coefficient and isolate it. move the term with the lowest coefficient so that it's alone on one side of its equation, then divide by the coefficient.
part e
now that you have one of the two variables in part d isolated, use substitution to solve for the two variables. you may want to review the multiplication and division of fractions and simplifying an expression primers. enter the answer as two numbers (either fraction or decimal), separated by a comma, with c first.

Arunner is jogging at a steady 3.6 km/hr. when the runner is 2.9 km from the finish line, a bird begins flying from the runner to the finish line at 14.4 km/hr (4 times as fast as the runner). when the bird reaches the finish line, it turns around and flies back to the runner. even though the bird is a dodo, we will assume that it occupies only one point in space, i. e., a zero-length bird. how far does the bird travel? (b) after this first encounter, the bird then turns around and flies from the runner back to the finish line, turns around again and flies back to the runner. the bird repeats the back and forth trips until the runner reaches the finish line. how far does the bird travel from the beginning? (i. e. include the distance traveled to the first encounter)