The variable z is directly proportional to x. When x is 10, z has the value 140.

What is the value of z when x = 20?

z = 280

Step-by-step explanation:

If two variables are directly proportional, it means that an increase in the value of one variable causes an increase in the value of the other variable. Also, a decrease in the value of one variable causes an decrease in the value of the other variable.

The variable z is directly proportional to x. If we introduce a constant of variation, the expression would be

z = kx

When x is 10, z has the value 140. It means that

140 = 10k

k = 140/10

k = 14

The equation becomes

z = 14x

the value of z when x = 20 is

z = 14 × 20

z = 280

step-by-step explanation:

always plug in x. in this case, x equals 4.

i'm going to first solve 4(2+3x)

1) 4(2+3(4)) use pemdas to solve.

i'm going to multiply whats in the parenthesis first, so 3 times 4=12.

2)4 (2+12) i'm then going to multiply 4 by both numbers in the parenthesis (because multiplying comes before adding)

4 times 2= 8.   4 times 12= 48

4) (8+48)= 56 (answer)

i'm then going to solve 8+12x and plug in 4 for x.

1) 8 +12(4)

multiplying comes before adding, so i'm gonna multiply 12 and 4.

12 times 4= 48.

2) 8+48=56

both equal the same!