Question

0,9(-8-3х) при х=4 -1/4(4/5у+9) при у=3 3/4 (у+1,6)*(-3)=19,2 (Х-0,6)*2,5=6 (1,8+у)*7=-22,4 (2+х)*3,1=-12,4 (у-1,9)*(-2,4)=12 (1,2+х)*(-5)=4

Answer 1

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Answer 2

To evaluate the given expressions, let's substitute the given values and solve each equation step by step:

1. For the expression 0.9(-8 - 3x) when x = 4: Substitute x = 4: 0.9(-8 - 3 * 4) = 0.9(-8 - 12) = 0.9(-20) = -18

2. For the expression -1/4(4/5y + 9) when y = 3: Substitute y = 3: -1/4(4/5 * 3 + 9) = -1/4(12/5 + 9) = -1/4(12/5 + 45/5) = -1/4(57/5) = -57/20

3. For the expression 3/4(y + 1.6)(-3) = 19.2: Divide both sides by -3: 3/4(y + 1.6) = 19.2 / -3 = -6.4 Multiply both sides by 4/3: y + 1.6 = -6.4 * 4/3 = -25.6/3 = -8.5333 Subtract 1.6 from both sides: y = -8.5333 - 1.6 = -10.1333

4. For the expression (x - 0.6) * 2.5 = 6: Divide both sides by 2.5: x - 0.6 = 6 / 2.5 = 2.4 Add 0.6 to both sides: x = 2.4 + 0.6 = 3

5. For the expression (1.8 + y) * 7 = -22.4: Divide both sides by 7: 1.8 + y = -22.4 / 7 = -3.2 Subtract 1.8 from both sides: y = -3.2 - 1.8 = -5

6. For the expression (2 + x) * 3.1 = -12.4: Divide both sides by 3.1: 2 + x = -12.4 / 3.1 = -4 Subtract 2 from both sides: x = -4 - 2 = -6

7. For the expression (y - 1.9) * (-2.4) = 12: Divide both sides by -2.4: y - 1.9 = 12 / -2.4 = -5 Add 1.9 to both sides: y = -5 + 1.9 = -3.1

8. For the expression (1.2 + x) * (-5) = 4: Divide both sides by -5: 1.2 + x = 4 / -5 = -0.8 Subtract 1.2 from both sides: x = -0.8 - 1.2 = -2

So, the values of the given expressions are:

1. 0.9(-8 - 3x) when x = 4: -18
2. -1/4(4/5y + 9) when y = 3: -57/20
3. 3/4(y + 1.6)(-3) = 19.2 when y = -10.1333
4. (x - 0.6) * 2.5 = 6 when x = 3
5. (1.8 + y) * 7 = -22.4 when y = -5
6. (2 + x) * 3.1 = -12.4 when x = -6
7. (y - 1.9) * (-2.4) = 12 when y = -3.1
8. (1.2 + x) * (-5) = 4 when x = -2