The kushites invented, which kind of writing?(a) hieroglyphs

No, the Kushites did not invent hieroglyphs. Hieroglyphs were developed by the ancient Egyptians around 3200 BCE. The Kushites, who ruled the region of Nubia (present-day Sudan) from approximately 800 BCE to 350 CE, used a script known as Meroitic. Meroitic is a writing system that has not been fully deciphered and is considered distinct from hieroglyphs.