MATH SOLVE

3 months ago

Q:
# Please help, I really need it....4. Which ordered pair is a solution to the system of equations? Use any method to solve. 2x - y = 53x + 2y = 4A. (5,5)B. (0,2)C. (2,-1) D. (-1,-7)12. What is the solution to the system of equations? Use the linear combination method. 3x+2y=75x-4y=19A. There are an infinite number of solutions. B. The solution is (3,-1).C. There is no solution.D. The solution is (5, 1).

Accepted Solution

A:

no 4.using substitution method2x - y = 5...(i)3x + 2y = 4...(ii)making y subject of formula in (i)2x-y=52x-5=ysubstitute y in (ii)3x+2(2x-5)=4opening bracket3x+4x-10=4collecting like terms3x+4x=4+107x=14dividing both sides by 77x/7=14/7x=2.but y=2x-5y=2(2)-5y=-1.solution=(2,-1)no.12.3x+2y=7...(i)5x-4y=19...(ii)multiply (i) by 2 and (ii) by 13x+2y=7}×25x-4y=19}×1we get;6x+4y=145x-4y=19adding the two equations,6x+5x=11x4y+-4y=014+19=33new equation11x=33divide both sides by 1111x/11=33/11x=3replacing x in (i)3x+2y=143(3)+2y=149+2y=142y=14-9dividing both sides by 22y/2=5/2y=5/2 or 2.5solution=(3,5/2) which is not in the choices.