Answer:
Sister = 15 years old
Brother = 12 years old
Step-by-step explanation:
Right now, if the brother is B years old and the sister is S years old, B = (4/5)S because the ratio from brother to sister is 4:5, so if one unit is X, B = 4X and S = 5X
Three years ago, the brother was B-3 years old and the sister was S-3 years old. Keeping one unit as X, we have
B = 3X
S = 4X
B-3 = (3/4)(S-3)
Therefore, we have a system of equations
B = (4/5)S
B-3 = (3/4)(S-3)
Substitute (4/5)S for B into the second equation to only have one variable
(4/5)S - 3 = (3/4)(S-3)
(4/5)S - 3 = (3/4)S - 9/4
add 3 to both sides and subtract (3/4)S from both sides to isolate the variable and its coefficient
(1/20)S = 3/4
multiply both sides by 20 to isolate the S
S = 15
B = (4/5)S = 12
Y=mx+b
m=slope
b=y intercept
we are given (3,-1)
one solution is x=3 and y=-1 or
when x=3 then y=-1
also slope=2
so
y=2x+b
subsitue 3 for x and -1 for y and solve for b
-1=2(3)+b
-1=6+b
subtract 6
-7=b
y=2x-7 is equation
answer is number 4
Answer:
The area of whole square is 396 sq mm
the area of triangle = 99
396 - 99 = 297 sq mm
Answer - 297
Turn the feet into meters 1 meter = 100cm and if there is 12cms in a foot than divide 100cm by 12cm and you get 8.3ft
