His work should have looked like this.
2x + y = 5
x − 2y = 10
y = 5 − 2x
x − 2(5 − 2x) = 10
x − 10 + 4x = 10
5x − 10 = 10 When he added in both sides, he subtracted 10 from 10,
5x = 20 instead of adding 10 from 10 to make 20.
x = 4
2(4) + y = 5
8 + y = 5
y = -3
Answer:
-4
Step-by-step explanation:
9^3 x 8 is the answer I believe
Answer:
Third option: 12x^2+8x+25
Step-by-step explanation:
s1=8x^2
s2=4x^2+15
s3=8x+10
Total perimeter of the pool edge: P
P=s1+s2+s3
Replacing s1, s2 and s3 in the formula above:
P=(8x^2)+(4x^2+15)+(8x+10)
P=8x^2+4x^2+15+8x+10
Adding like terms:
P=12x^2+8x+25
