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Click here to watch ALL difficulties on Systems-of-equationsQuestion 289082: which ordered pair is a solution of the device of equations y=x^2-x-20 and y=3x-15?I did do some work i didy=x^2-x-20 y=(x^2-5x)(4x-20)y= x(x-5) 4(x-5)= y=(x+4)(x-5)andy=3x-15y=3(x-5)but i don"t recognize what to perform from there, i would certainly appreciate the help Found 2 services by Fombitz, dabanfield:Answer by Fombitz(32379)
(Show Source): You deserve to put this systems on your website! because they both same y, set them same to each other and solve because that x.Then go earlier and fix for y.You"re fixing for the intersection the a line and also a parabola. You can factorTwo solutions:Then use either y,(5,0)...(-1,-18)...Graphically prize by dabanfield(803)
(Show Source): You have the right to put this systems on her website! i beg your pardon ordered pair is a systems of the device of equations y=x^2-x-20 and y=3x-15? ns did do some work i did y=x^2-x-20 1.) y=(x^2-5x)(4x-20)y= x(x-5) 4(x-5)= y=(x+4)(x-5) and also y=3x-15y=3(x-5) yet i don"t know what to do from there, i would certainly appreciate the helpYour factoring at 1.) is no correct.Here"s an additional approach:2.) y = x^2 - x - 203.) y = 3x - 15 native 2.) we recognize we deserve to substitute 3x - 15 because that y in equation 1.)3x - 15 = x^2 - x - 20x^2 - 4x - 5 = 0(x - 5)*(x + 1) = 0x = 5 and also x = -1 are options for x. Substituting x = 5 in 3.) us have:y = 3*5 - 15 y = 15 - 15 = 0So the point (5,0) is the very first "possible" solution to the system.The various other solution, substituing -1 for x:y = 3*(-1) - 15y = -3 - 15 = -18So the suggest (-18, -1) is the seocnd possible solution to the system.Let"s examine each soluiton in 2.):First (5,0):Does 0 = 5^2 - 5 - 20?5^2 - 5 - 20 = 25 - 5 - 20 = 0Yes, therefore (5,0) is a systems to both equations.
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How around (-18,-1)?Does -1 = (-18)^2 - 18 - 20(-18)^2 - 18 - 20 = 324 - 38 = 286286 is not equal to -1 therefore (18,-1) is not a systems to the system.