3 questons

Question

value of x that results in the required y value
5x2=7
x=1, 1.1 ,1.2 ,1.3, 1.4, 1.5
y=

x2-7x+10=5
x=0.5, 0.6, 0.7, 0.8, 0.9, 1
y=

3x2-5x=2
x=1, 2, 3, 4, 5,
y=

Answer 1

5x²=7
x²= 7/5
x = ±√(7/5)
x = ±√1.4
x ≅ 1.2 from the choices given
 
x²-7x+10=5
x²-7x+5=0

Quadratic equation a=1, b=-7, c=5  x = -b/2a ±(√(b²-4ac))/2a

x = 7/2(1) ±[√((-7)²-4(1)(5))]/2(1)

x = 3.5 ±[√(49-20)]/2

x = 3.5 ±(√29)/2

x = 6.1926   or  .80742

x≅0.8 from the choices given

 

3x²-5x=2

3x²-5x-2=0

We can factor this by grouping

3x²-6x + x -2 = 0

3x(x-2) + (x-2) = 0

(3x+1)(x-2)=0

either  3x + 1 = 0    or    x-2 = 0

          3x=-1

           x = -1/3       or    x=2

x=2 From the choices given