Jse prime Pactors to determine the HCF of 90 and 126

18

Step-by-step explanation:

first use the factor tree to find the factors of 90 and 126

90={2×3×3×5}

126={2×3×3×7}

for HCF take common factors with low exponents

HCF={2×3×3}

18

answer: c.  

step-by-step explanation:

mixtures containing substances that get attracted to magnet can be separated using a magnet. we can separate iron from a mixture of sand and iron, as only iron attracts to the magnet.