Algebra 2, Pt.16b, Chapter 1

Service Description

For another example, 1.26 tells us to Solve the system{2x-3y=9 and x-5y=-6; Solution is If the second equation is multiplied by -2, the coefficients of x will be opposites. 2x-3y = 9 2x-3y = 9 -2(x-5y =-6) -2x +10y =12 x-5(3) =-6 ________________ 7y =21 x-15 = -6 y =3 x=9 The solution is (9,3). Example 1.27 tells us to Solve the System {5y = 11 -2x and 3x = 4y -18 Solution First, note that the equations must be rearranged into the general form: 2x + 5y = 11 3x -4y = -18 Now, multiply the first equation by 3 (the coefficient of x in the second equation) and the second equation by -2 (the opposite of the coefficient of x in the first equation) to eliminate x. 3(2x + 5y =11) 6x + 15y = 33 to 2x + 5(3) = 11 -2(3x -4y = -18) -6x + 8y = 36 2x + 15 = 11 ------------------- 23y = 69 2x = -4 y = 3 x = -2 The solution is (-2, 3) After this next Lesson we may have to enter material on the second Wednesday of next week to finish up before tests for those learning Algebra 2.