Maria = x
Tom = y
Use substitution
x+y=30
2y=x
2y+y=30
3y=30
y=10
Tom is 10 years old.
x+y=30
x+10=30
x=20
Maria is 20 years old.
Answer:
109
Step-by-step explanation:
Hope this helped :)
Step-by-step explanation:
Answer:
(x,y,z)=( -2, -1 ,5)
Step-by-step explanation:
9x+2y-27z=-155 (1)
-11x-y+37z=208 (2)
19x+6y-52z=-304 (3)
(1) *3 ;(2) *6 ;(3)*1, you have
27x+6y-81z=-465 (1)
-66x-6y+222z=1248 (2)
19z+6y-52z=-304 (3)
(1) +(2), you have
-39x+141z= 783 (4)
(4) /3, you have
-13x +47z=261 (4)
(2) +(3), you have
-47x+170z=944 (5)
From ( 4) and (5), you have equations
-13x +47z=261 (4)
-47x+170z=944 (5)
(4)*(-47); (5)*13, you have
611x-2209z=-12,267 (4)
-611x+2210z=12,272 (5)
(4)+(5), you have
z=5
Replace z=5 in (4), you have
611x- 2209*5=-12,267
611x- 11,045 =-12,267
611x=-1222
x= -2
Replace x=-2, z=5 in (1) , you have
9*(-2) +2y -27*5=-155
-18+2y-135=-155
-18+2y=-20
2y=-2
y=-1
Result (x,y,z)=( -2, -1 ,5)
144 is divisible by 3 and 4.
