The term 2.1 × 10^2 has 2 significant figures, so the final answer should be rounded to 2 significant figures.

Substituting x = 2 into the equation gives 5(2) + 3y = 15, which simplifies to 10 + 3y = 15. Thus, 3y = 5, and y = 5/3.

Substituting x = 2 into the equation gives 5(2) + 3y = 20. This simplifies to 10 + 3y = 20, leading to 3y = 10, thus y = 10/3, which is approximately 3.33. The closest integer option is 4.

The mode is 4, as it appears most frequently (three times) in the data set.

The mode is 4, as it appears most frequently (three times) in the data set.

The mode is 12, which appears three times, more than any other number.

The mode is 70, as it appears 3 times, which is more than any other score.

From 2 moles of Fe, 2 moles of FeCl3 are produced. Therefore, from 4 moles of Fe, 4 moles of FeCl3 are produced.

2 moles of Na produce 2 moles of NaCl. Molar mass of NaCl = 58.5 g/mol. Therefore, 2 moles of NaCl = 2 × 58.5 g = 117 g.

4 moles of Na produce 4 moles of NaCl. Molar mass of NaCl = 58.5 g/mol. Therefore, 4 × 58.5 = 236 g.

From 2 moles of Na, 2 moles of NaCl are produced. Therefore, from 4 moles of Na, 4 moles of NaCl are produced.

The mode is 30, as it appears 3 times, more than any other number.

The mode is 8, as it appears 3 times, which is more than any other number.

The mode is 4, as it appears 3 times, more than any other number.

The mode is 5, as it appears 2 times, while 8 also appears 2 times. However, 5 is the smallest mode.

In an isosceles triangle, angles opposite to equal sides are equal. Therefore, angle B = angle C = (180 - 40) / 2 = 70 degrees.

The sum of angles in a triangle is 180 degrees. Therefore, angle C = 180 - (30 + 60) = 90 degrees.

In an isosceles right triangle, the sides opposite the 45-degree angles are equal. DE = DF/√2 = 10/√2 = 5√2 cm.

Since two angles are equal (45 degrees), triangle DEF is an isosceles triangle.

Since two angles are equal (45 degrees), triangle DEF is an isosceles triangle.

Semi-perimeter s = (12 + 16 + 20) / 2 = 48 / 2 = 24 cm.

Using the Pythagorean theorem, 5^2 + 12^2 = 25 + 144 = 169 = 13^2. Thus, triangle DEF is a right triangle.

Using the sine rule, HI/sin(60) = GH/sin(30). Therefore, HI = (10 * sin(60)) / sin(30) = 10 * (√3/2) / (1/2) = 10√3 cm.

Using the Pythagorean theorem, GI = √(HI² - GH²) = √(12² - 9²) = √(144 - 81) = √63 = 15 cm.

Using Heron's formula, semi-perimeter s = (10 + 24 + 26) / 2 = 30. Area = √(s(s-a)(s-b)(s-c)) = √(30*20*6*4) = 120 cm².

The longest side of triangle GHI is GI, which measures 26 cm.

Perimeter = GH + HI + GI = 10 + 24 + 26 = 60 cm.

Since the sides are in the ratio 3:4:5, it follows the Pythagorean theorem, indicating it is a right-angled triangle.

Using the Pythagorean theorem, JL = √(KL² - JK²) = √(20² - 15²) = √(400 - 225) = √175 = 12.25 cm.

Using Pythagoras theorem: JL = √(KL² - JK²) = √(20² - 15²) = √(400 - 225) = √175 = 12 cm.