
William W. answered 06/04/20
Math and science made easy - learn from a retired engineer
Solving a "system of equations" means you are looking for the point or points that comply to both equations. That would mean the y-value of one equation would equal the y-value of the other equation so, since y = -16x2 + 18x + 5 and also y = 1.5x then:
-16x2 + 18x + 5 = 1.5x
-16x2 + 16.5x + 5 = 0
Using the quadratic formula:
x = [-b ± √(b2 - 4ac)]/(2a)
x = [-16.5 ± √(16.52 - 4(-16)(5))]/((2)(-16))
x = [-16.5 ± √592.25]/(-32)
x = [-16.5 ± 24.336]/(-32)
x = -0.245 and x = 1.276
Often times negative answers are discarded because they may not make sense in real world situations. I'm not sure what a negative in this situation means - the problem seems a bit vague.