gmat prep question

1. Simplest way I see to do this one is just to list the days. Since all the answer options are in May, you know you won't have to go too far out to find a common day. So,

Uniforms - May 3rd, 10th, 17th, 24th, 31st
Linens - May 4th, 9th, 14th, 19th, 24th, 29th

E.

2. We have equations for y and z both in terms of x. Therefore, we can write y=2z as

x^2 - 5x + 14 = 2(x^2 - x + 2)
x^2 - 5x + 14 = 2(x^2) - 2x + 4
0 = x^2 + 3x -10
0 = (x-2)(x+5)

So, x = 2 or -5

A restaurant receives clean uniforms on May 3 and every 7 days thereafter. The restaurant receives clean linens on May 4 and every 5 days thereafter. On what date in May does the restaurant receive both clean uniforms and clean linens?
A. may 3
B. may 10
C. may 17
D. may 19
E. may 24

Uniforms - May 3, May 10, May 17, May 24, May 31
Linen - May 4, May 9, May 14, May 19, May 24, May 29
Hence May 24

If y= x^2-5x+14 and z= x^2-x+2, what is the set of all values of x for which y=2z?
A. (-5)
B. (2)
C. (3)
D. (-2, 5)
E. (-5,2)

E??